The NYPD cracked down on Tuesday night by arresting more than 280 people and blocking 5,000 protesters from entering Manhattan by holding them up on the Manhattan Bridge while enforcing the 8pm curfew.
It remains unclear if all 280 were arrested for breaking the curfew or if other offenses, like looting, were included in that number but it is a drastic reduction from the 700 that were arrested by Tuesday morning after a frightening 48-hour period that saw entire shopping districts in the city ransacked and ruined.
The curfew was brought forward from 11pm to 8pm on Tuesday and has been extended until Monday morning - when New York City begins its phase 1 of reopening after recovering from being the epicenter of the coronavirus pandemic.
In response to the frightening chaos that unfolded across Manhattan on Sunday and Monday night and growing criticism over the city's handling of it.
President Trump was among critics who said the city was 'totally out of control' and claimed the National Guard needed to be brought in.
After scrambling to keep up with looters on Monday night, NYPD officers - who all had their leave canceled on Tuesday - were seen arresting protesters for breaking curfew on Tuesday all over Manhattan.
They blocked a huge protest on the Manhattan Bridge, stopping some 5,000 marchers who planned to enter the city from Brooklyn.
After holding the protesters on the bridge for more than two hours in a tense stand-off, the protesters retreated peacefully back into Brooklyn.
Some businesses, still unwilling to put their faith in the NYPD, have hired private security.
5,000 protesters were stopped from entering Manhattan after walking across the Manhattan Bridge on Tuesday night
The NYPD stopped 5,000 protesters from entering Manhattan by blocking them on the Manhattan Bridge on Tuesday night. The protesters retreated after 2 hours
Protesters leave the Manhattan Bridge after being stopped by police last night during an 8pm curfew which thousands ignored but which was followed by less rampant destruction than on previous days in New York City
Young protesters wearing coronavirus masks sit behind their hands behind their backs
Protesters arrested on Tuesday night in Manhattan after breaking the 8pm curfew set by the city to get a handle on the chaos. One man had blood streaming from his head as he had his hands put in wire ties
A woman cries on the ground while sitting with her hands in wire ties after being arrested for breaking curfew on Tuesday night
NYPD officers wait for protesters to block their entry into Manhattan on the Manhattan Bridge on Tuesday night
Dozens of people were seen being taken away in paddy wagons as NYPD cracked down on curfew-violators
Saks Fifth Avenue on Wednesday was surrounded by a militia of private, armed guards. They held dogs on leashes and stood in front of plywood walls that had been reinforced with razor wire to protect the luxury department store.
'Anyone who is out and cannot prove they are there for essential reasons can be detained,' Mayor de Blasio said on Wednesday morning, warning against anyone who thinks they can flout the curfew.
Mayor Bill de Blasio said on Wednesday that the situation overnight was a vast improvement on the previous 48 hours.
Trump claimed on Tuesday that the city was 'totally out of control'. On Wednesday, he said the National Guard was 'ready'.
Gov. Cuomo was hesitant to call in the Guard as was de Blasio. They both said the NYPD could handle it in a better way.
The calmer scenes in New York City were echoed across much of America where protesters once again turned out in force but the confrontations with police were subdued and widespread rioting was limited.
Saks Fifth Avenue has hired its own security guards and placed razor wine fencing around its iconic store front
The luxury store's plywood window coverings were reinforced on Wednesday morning
Rows of private security guards stood in front of the store on Wednesday to ward off any looters
A security guard standing outside the store on Wednesday morning
The store had already been boarded up after two nights of chaos across New York City
Security guards with dogs outside Saks Fifth Avenue on Wednesday morning
It followed a day of anger from President Trump's critics over the way he threatened to deploy the military to quell riots across the US and cleared protesters in Washington DC so he could visit damaged St John's Episcopal Church.
He also considered using 'tanks' or other armored military vehicles to help restore order in the US after violent protests broke out across the country for a sixth night, defense officials have revealed.
This morning the president repeated his demand for 'LAW & ORDER!', urged police to 'get tough' and responded to an image of a boarded-up Manhattan with a warning that 'the National Guard is ready'.
In New York, De Blasio moved the city's first curfew since 1943 forward from 11pm but rejected Trump's urging and an offer from Governor Andrew Cuomo to bring in the National Guard.
Looters broke into Zara near the World Trade Center, Nordstrom Rack on 6th Avenue, fought with Guardian Angels at Foot Locker in the East Village and stores were also targeted in Soho again.
As unrest continued for a fifth night, Trump called on officials to enlist the help of the federal government to regain control of the city.
A young woman is arrested after breaking curfew at Astor Place. It is unknown if she was part of the group that smashed store fronts and looted stores there
The Starbucks at Astor Place on Tuesday night had all its windows smashed
They set fire to garbage near Astor Place after smashing windows of stores
People being arrested at Astor Place on Tuesday night. It is unclear if they were arrested for looting or for breaking curfew
'New York's Finest are not being allowed to perform their MAGIC but regardless, and with the momentum that the Radical Left and others have been allowed to build, they will need additional help. NYC is totally out of control. [De Blasio and Cuomo] MUST PUT DOWN RIOTING NOW!' he tweeted.
Mayor de Blasio later defended his decision not to deploy National Guard troops, telling CNN their presence could have raised 'a real risk of violence and someone losing their life.'
He also hit back at New York governor Cuomo who has been highly critical of De Blasio's approach to controlling the riots. He said after Tuesday night's chaos: 'The NYPD and the mayor did not do their job last night,' Cuomo had said at a briefing in Albany. 'Look at the videos. It was a disgrace.'
De Blasio hit back:'He dishonored the men and women of the NYPD in an absolutely inappropriate way for any leader to do. Any elected official who blames the NYPD while they were out there fighting in the streets to restore order, protect 'people — that's disgraceful.'
He also confirmed Tuesday night saw 'the highest number of police we have had over the last five days,' but refused to say how many officers were on the ground.
NYPD officers load detained demonstrators on to a paddy wagon after thousands ignored 8pm curfew
Looters broke into Zara near the World Trade Center, Nordstrom Rack on 6th Avenue, fought with Guardian Angels at Foot Locker in the East Village and stores were also targeted in Soho again.
People are arrested for looting at Astor Place in New York City last night as police swooped on people who broke the city's curfew
People are arrested after looting in New York City last night on another day of angry protests following the death of George Floyd in Minneapolis last week
Dozens of protesters and curfew-violators were detained and loaded onto police vans at Grand and Centre Street in as chaos erupted a fifth night
Police began making arrests around 9pm, when peaceful protests turned into chaos on Tuesday night
A demonstrator is detained by a police officer after curfew during a protest against the death of George Floyd
President Donald Trump has the highest disapproval rating of any president at this point in office, according to a new poll.
Opinion poll analysis website FiveThirtyEight shared startling numbers showing that Trump's disapproval rate is at 54 percent, the highest it's been since October 2019.
'Trump's disapproval rating has been on the rise again, now up to 54 percent. There were some presidents with lower approval ratings to this point in their first terms, but no president had a higher *disapproval* rating than Trump now has,' site creator Nate Silver tweeted Tuesday.
As of 1am, police had carried out about 200 arrests across the city, with that figure expected to rise, CNN reported.
Shortly after the curfew went into effect, De Blasio had urged residents to go home 'so we can keep people safe', but he was ignored by many around the city who continued protesting throughout the city's streets.
In some areas, police let people continue on their way, while making arrests in others. Demonstrators who had been on the West Side Highway in lower Manhattan were herded off, with parts of the roadway blocked off behind them.
Police began making arrests around 9pm and shut down parts of the West Side Highway in lower Manhattan, blocking it off to huge crowds of protesters.
The police department had announced it would not allow vehicle traffic south of 96th Street in Manhattan after curfew, though residents, essential workers, buses and truck deliveries were exempt.
An estimated 5,000 peaceful protesters were also left stranded on the Manhattan Bridge for hours after NYPD officers formed a barricade blocking entry into Manhattan after the curfew came into effect.
Videos shared on social media showed demonstrators chanting 'let us through' after reaching the end of the bridge.
Some took to Twitter to say they were forced to wait for two hours before officers finally let crowds through.
'Currently stuck on the Manhattan Bridge. NYPD told us the would let us through 'in 10 min' - that was 40 min ago. They now brought in multiple vans to barricade us in from both sides. They are all wearing riot gear. We have been nothing but peaceful,' one woman tweeted.
Social media footage showed protesters finally began to clear the bridge around 11pm.
Meanwhile in Chelsea, protester Jane Rossi said she witnessed officers rip a man out of his car and arrest him around 10.45pm.
The car was behind a group of several hundred protesters that had roamed Manhattan peacefully since leaving Trump Tower at 8pm.
NYPD officers board a bus after securing the Soho area to prevent looters during curfew following demonstrations
Tensions had risen moments earlier when some in the group began trying to damage a bike rental station and banged on the windows of a JCPenny's. The vast majority of the crowd moved to stop the them.
Officers surrounded the car and arrested the driver moments later.
'They were just driving behind the protesters making sure that we were safe,' Rossi told AP. 'They were part of the protest.'
Just after midnight Wednesday, most of the city's streets were cleared aside from police patrolling, especially in hot-spot areas for demonstrations in areas of Brooklyn and Manhattan.
There was a heavy police presence in the Brooklyn neighborhood of Crown Heights, where authorities say police fatally shot a man after responding to reports of shots fired. NYPD Chief of Department Terence Monahan said the officer-involved shooting was not connected to the protests.
Looters also took to the streets to target businesses for a fourth night, with one video showing a group of men breaking into a Zara store.
Footage uploaded on Twitter showed police tackling a group of looters to the ground as they emerged from a Zara store near Fulton St, before placing them in handcuffs.
Merchants were seen boarding up storefronts in a bid to protect their businesses from looters who have targeted high-end designer stores on Manhattan's iconic Fifth Ave, as well as the Macy's flagship store.
Protests over the death of George Floyd had continued across the city this afternoon, with large gatherings forming in Foley Square near City Hall, Times Square, Washington Square Park and Carl Schurz Park.
Demonstrators marched peacefully, with some staging a sit-in near Carl Schurz Park on the Upper East Side, before chaos erupted across the city again after sunset.
It comes as officials had been gearing up for another night of carnage. The NYPD earlier had also told cops to cancel any time off in a message sent to staff reading: 'Effective immediately, all full duty uniformed members of the service RDO's are cancelled.'
Police guard the entrance to the Manhattan Bridge that heads towards Brooklyn as protesters try to cross over
Thousands of people took to the streets of NYC for a fifth night on Tuesday peacefully protesting the death of George Floyd
A number of demonstrations were scheduled for Tuesday afternoon as Mayor Bill de Blasio was forced to bring curfew forward from 11pm to 8pm after last night's carnage
A woman holds up a Black Lives Matter sign during fifth night of George Floyd protests in NYC on Tuesday
Protesters chanting 'hands up, don?t shoot!' march down Flatbush Avenue, one of Brooklyn's major streets, towards the Manhattan Bridge
Protesters take a knee as a sign of unity and chant during a solidarity march for George Floyd in Times Square
The daytime protests comes as the NYPD announced all non-essential traffic will be banned across Manhattan south of 96th Street starting at 8pm tonight
Protesters chant during a solidarity march for George Floyd in Times Square Tuesday
Protesters take a knee outside of the police station in Times Square in New York City on Tuesday
New York courts had also warned their workers to stay at home because of the protest.
'The entire area around the courthouse complex will be shut down,' District Executive Edward Friedland wrote in the email, obtained by The New York Post.
'At the direction of the Chief Judge [Colleen McMahon], no SDNY staff are to come to the Foley Square courthouses tomorrow.'
One protest was scheduled to be held at 1 Police Plaza, the headquarters of the New York City Police Department, but organizers changed its location in order to not interfere with protesters in custody being released at the station, according to Patch.
Further demonstrations in the city were planned at the Stonewall Inn and 47th Street and Broadway, in Manhattan, 98 Fifth Ave in Brooklyn, and Fort Totten and Far Rockaway-Mott Avenue Station in Queens.
NBC reporter Phil McCausland posted to Twitter that thousands gathered in Foley Square Tuesday afternoon before they began a march north through the city.
Before they started out, protesters took a knee, raised a fist and chanted the names of George Floyd and Breonna Taylor while helicopters circled overhead.
As they walked north, they were saluted by medical workers holding signs that read, 'Nurses fought COVID. Now we'll fight the police.'
Workers putting up plywood to protect businesses from further looting also showed their support banging on wood and holding 'Black Lives Matter' signs.
In Times Square, thousands of protesters took a knee while holding their fists up in solidarity.
Other protests unfolded at Carl Schurz Park in the Upper East Side, as well as Washington Square Park where organizers planned to march uptown towards the mayor's residence Gracie Mansion.
Footage shared on social media Tuesday evening showed thousands marching peacefully, a stark contrast to Monday night's protests.
At Carl Schurz Park, photos showed demonstrators staging a sit-in and sitting on the road in silence.
Police officers stand guard in Lower Manhattan as protesters march through the city
Thousands took a knee as they gathered in Foley Square in Lower Manhattan in a peaceful protest that comes after four nights of chaos
As of early Tuesday evening, the city protests unfolded peacefully - a stark contrast to Monday night's riots
Protesters spilled onto the streets of Manhattan ahead of the city's 8pm curfew tonight
Protests broke out in Washington Square Park where organizers planned to march uptown towards the mayor's residence Gracie Mansion
Around the country, last night's protests were largely peaceful and the nation's streets calmer - although tensions flared just before a 9pm curfew went into effect in Atlanta.
Officers launched tear gas into crowds and were met with an onslaught of water bottles and fireworks before the crowd eventually dispersed.
Tens of thousands gathered in Houston to pay a hometown tribute to Floyd, who grew up in the Texas city and is to be buried there next week.
'Today is... about George Floyd's family - we want them to know that George did not die in vain,' Mayor Sylvester Turner told an estimated 60,000 people.
A tearful Roxie Washington, the mother of Floyd's six-year-old daughter, told a news conference she wanted 'justice for him because he was good. No matter what anybody thinks, he was good.'
Elsewhere, the Pentagon confirmed that around 1,600 active duty troops had been moved to the DC area from Fort Bragg in North Carolina and Fort Drum in New York to assist authorities in containing the unrest in Washington.
Law enforcement met with some resistance as they tried to clear protesters from near the White House. A fence was later put up to stop protesters from getting too near to the President's official residence.
And in Los Angeles, dozens of protesters staged a post-curfew sit-in outside Mayor Eric Garcetti's home. They held up their hands and chanted: 'Peaceful protest' while ignoring police orders to move.
ATLANTA, GEORGIA: The National Guard and cops were massed together as they faced down scattered protesters who had defied a 9pm curfew
WASHINGTON DC: Law enforcement in the nation's capital were met with similar resistance as they attempted to clear the streets outside the White House
BOSTON: Protesters set of fireworks following a rally honoring George Floyd on Tuesday night
ORLANDO: Police deploy tear gas to disperse crowds outside Orlando City Hall on Tuesday night
Revealed: Trump considered using military 'tanks' and ordered helicopters to blast protesters with their downdraft as hundreds of soldiers armed with BAYONETS are deployed to Washington
President Donald Trump considered using 'tanks' or other armored military vehicles to help restore order in the US after violent protests broke out across the country for a sixth night, defense officials have revealed.
As protests over the death of George Floyd enter their second week, Trump has threatened to deploy active duty military across the country to quell the unrest.
On Monday, law enforcement officials pushed hundreds of protesters out of Washington's Lafayette Park, ahead of the district's 7pm curfew.
A senior White House official, who spoke on the condition of anonymity, revealed on Tuesday that Trump hoped to make the aggressive action in Washington an example for the rest of the country.
Two Pentagon officials also told AP that the president had ordered military aircraft to fly above the capital on Monday night as a 'show of force' against demonstrators.
They did not say how many or what type of aircraft had been mobilized.
Videos and photographs posted on social media showed helicopters flying low over buildings and hovering just above groups who were on the street despite a district-wide curfew.
Law enforcement paired the tactic with heavy use of tear gas, pellets and chemical spray as protesters marched toward the White House.
Trump's tactics were decried on Tuesday by some fellow Republicans as well as his presumptive Democratic opponent Joe Biden.
Show-of-force missions are designed to intimidate and, in combat zones, warn opposing forces of potential military action if provoked.
Three senior defense officials also told The Daily Beast that the idea of deploying military forces was being pushed by the White House, not the Pentagon.
The sources revealed Trump consulted with aides about using military vehicles or 'the kind of hardware' used by the armed forces, to help bring the chaos under control.
Hundreds of people gathered for the demonstration at the Lincoln Memorial Reflecting Pool on Washington DC's fifth consecutive day of protests following the death of George Floyd
One official said Trump did not specifically order 'tanks' to patrol the streets, but said he mentioned it in discussions because 'I think that is just one of the military words he knows'.
It comes as 700 soldiers dressed in riot gear and armed with bayonets arrived at two military bases near Washington on Tuesday evening, while another 1,400 are preparing to mobilize, as the nation's capital braces for another night of chaos.
Hundreds of members of the Army's 82nd Airborne Division were called earlier after Trump promised a more aggressive approach on the violence and riots unfolding across the country.
Defense officials told AP the US military and National Guard were operating under the mission name 'Operation Themis' - named after the titaness of divine law and order.
Moments after the historic Lafayette Park was cleared of protesters on Monday, Trump walked across to pose with a Bible in front of a church damaged by fire during protests the previous evening.
He hoped his personal walk to the church would send a message about how dominant force could restore law and order, sources said.
'D.C. had no problems last night. Many arrests. Great job done by all. Overwhelming force. Domination,' Trump tweeted Tuesday, after a night in which heavily armed military forces and federal officers swarmed the city.
Trump added: '(thank you President Trump!).'
In an evening address in the Rose Garden on Monday, Trump called on governors to ramp up the National Guard presence in their states to tamp down the protests.
If they didn't abide by those orders, Trump said, he would dispatch the military to their states - a step rarely taken in modern American history.
'SILENT MAJORITY!' Trump tweeted Tuesday, embracing a phrase popularized by President Richard Nixon decades ago, in claiming broad support for his actions. Trump also emphasized the political importance of the moment to his supporters on Twitter and declared that 'My Admin has done more for the Black Community than any President since Abraham Lincoln.'
The District of Columbia's federal status gives the president outsized authority to act, allowing him to direct the deployment of the National Guard.
He authorized Attorney General William Barr to oversee a surge in the deployment of federal law enforcement officers, including the FBI's Hostage Rescue Team and agents from the Drug Enforcement Agency.
Stunning photos show the officers clad in full riot gear lined up in separate rows as they stared down at the crowds
Dozens of National Guard troops stood watch over a peaceful protest in front of the Lincoln Memorial in an extraordinary show of military force on Tuesday evening
Defense Secretary Mark Esper and Gen. Mark Milley, the chairman of the Joint Chiefs of Staff, sought to distance themselves from Monday night's events after former military officials criticized their appearance with the president.
Senior defense officials told reporters the two were not aware that the Park Police and law enforcement had made a decision to clear the square or that Trump intended to visit the church.
They had been in Washington to coordinate with federal law enforcement officials but were diverted to the White House to brief Trump on military preparations, the officials said.
Former chairman of the joint chiefs Mike Mullen excoriates Donald Trump saying his orders cannot be trusted, warning president will 'politicize' the troops and saying: 'Citizens are not the enemy'
By Geoff Earle, Deputy U.S. Political Editor For Dailymail.com
Former Chairman of the Joint Chiefs of Staff Mike Mullen broke his silence Tuesday to say he was 'sickened' by the use of U.S. National Guard forces to push protesters out of Lafayette park to make way for President Trump's photo-op.
'I am deeply worried that as they execute their orders, the members of our military will be co-opted for political purposes,' Mullen warned.
'I have to date been reticent to speak out on issues surrounding President Trump's leadership, but we are at an inflection point, and the events of the past few weeks have made it impossible to remain silent,' Milley wrote in the Atlantic.
President Donald Trump walks with US Attorney General William Barr (L), US Secretary of Defense Mark T. Esper (C), Chairman of the Joint Chiefs of Staff Mark A. Milley (R), and others from the White House to visit St. John's Church after the area was cleared of people protesting the death of George Floyd June 1, 2020, in Washington, DC
Trucks transport District of Columbia National Guard troops along West Executive Drive in support of law enforcement officers that are keeping demonstrators away from the White House June 01, 2020
Mullen termed Trump's staged visit to fire-damaged St. John's church Monday a 'stunt' that raised serious issues about the role of the military in U.S. society.
'Whatever Trump's goal in conducting his visit, he laid bare his disdain for the rights of peaceful protest in this country, gave succor to the leaders of other countries who take comfort in our domestic strife, and risked further politicizing the men and women of our armed forces.'
He called attention to 'institutional racism' and 'police brutality' in the wake of the death of Geroge Floyd at the hands of police, while also condemning street violence.
His op-ed comes a day after Trump declared himself the 'law and order president' and said he would deploy 'thousands and thousands' of troops to American cities to restore order.
Mullen said he didn't have confidence in the orders Trump would give – and said it would be inappropriate to use the 1807 Insurrection Act as the basis for using U.S. troops to impose order on U.S. cities. Federal law generally prohibits the use of the military for domestic purposes.
'I remain confident in the professionalism of our men and women in uniform,' Mullen wrote.
Former Jt. Chiefs chair Gen. Martin Dempsey wrote that America was not a 'battleground,' after Defense Sec. Mark Esper spoke of dominating the 'battle-space' here
'They will serve with skill and with compassion. They will obey lawful orders. But I am less confident in the soundness of the orders they will be given by this commander in chief, and I am not convinced that the conditions on our streets, as bad as they are, have risen to the level that justifies a heavy reliance on military troops,' he added.
'Certainly, we have not crossed the threshold that would make it appropriate to invoke the provisions of the Insurrection Act.
The retired Navy admiral served under Presidents George W. Bush and Barack Obama from 2007 through 2011.
Mullen's successor as chair of the joint chiefs, General Martin Dempsey, also blasted Trump's move.
'America's military, our sons and daughters, will place themselves at risk to protect their fellow citizens. Their job is unimaginably hard overseas; harder at home. Respect them, for they respect you. America is not a battleground. Our fellow citizens are not the enemy,' Dempsey wrote. '#BeBetter,' he concluded, in what could be a take on first lady Melania Trump's Be Best campaign.
The current chair of the joint chiefs, Gen. Mark Milley, was seen in battle fatigues accompanying Trump on his walk to St. John's.
Just minutes after Mullen's article was posted, the Washington Post reported on the use of military helicopters with red cross insignia being used to show force to protesters was being called a 'foolish move' by Geoffrey Corn, a former Army lawyer.
HOW TRUMP MIGHT - JUST - BE ABLE TO SEND IN TROOPS THANKS TO THE 1807 INSURRECTION ACT
Trump's dramatic declaration that he would impose troops on American cities if governors defied him sets up the possibility of an epic constitutional clash in a situation with little real precedent in American history.
Trump did not say what his power was, but it is the Insurrection Act of 1807. On the face of it, it allows him to send in troops.
But using that Act raises a series of questions about what courts would do - and even whether the armed forces would obey him.
WHAT INSURRECTION ACT ACTUALLY SAYS
Whenever there is an insurrection in any against its government, the President may, upon the request of its legislature or of its governor if the legislature cannot be convened, call into Federal service such of the militia of the other, in the number requested by that, and use such of the armed forces, as he considers necessary to suppress the insurrection.
Whenever the President considers that unlawful obstructions, combinations, or assemblages, or rebellion against the authority of the United, make it impracticable to enforce the laws of the United in any by the ordinary course of judicial proceedings, he may call into Federal service such of the militia of any, and use such of the armed forces, as he considers necessary to enforce those laws or to suppress the rebellion.
The President, by using the militia or the armed forces, or both, or by any other means, shall take such measures as he considers necessary to suppress, in a State, any insurrection, domestic violence, unlawful combination, or conspiracy, if it
(1) so hinders the execution of the laws of that State, and of the United States within the State, that any part or class of its people is deprived of a right, privilege, immunity, or protection named in the Constitution and secured by law, and the constituted authorities of that State are unable, fail, or refuse to protect that right, privilege, or immunity, or to give that protection; or
2) opposes or obstructs the execution of the laws of the United States or impedes the course of justice under those laws.
In any situation covered by clause (1), the State shall be considered to have denied the equal protection of the laws secured by the Constitution.
Whenever the President considers it necessary to use the militia or the armed forces under this chapter, he shall, by proclamation, immediately order the insurgents to disperse and retire peaceably to their abodes within a limited time.
WOULD HE REALLY USE A LAW FROM 1807?
Basically, yes. In the 1790s Militia Acts, Congress gave the president specific powers to call up militias - the forerunner of federalizing the National Guard.
In 1807 the Insurrection Act made clear that, in addition, the president can call up 'such part of the land or naval force of the United States as shall be judged necessary.'
It has not been changed substantially since but was amended in 1871, allowing the president to use it to enforce the Fourteenth Amendment - a civil rights amendment passed after the Civil War.
Another amendment in 2007, in the wake of Hurricane Katrina, made clear that the president can call up troops in the case of natural disasters.
WHAT WOULD HE DO?
The law's only requirement is a proclamation, to 'order the insurgents to disperse and retire peaceably to their abodes within a limited time.'
Once that time has passed, Trump can move in troops.
Trump also has to report to Congress on what he is doing and why.
SO DOES IT GIVE TRUMP THE POWER HE CLAIMS TO SEND IN THE MILITARY ON HIS OWN?
The simple answer is yes, it does.
But the more complicated answer could lead to a constitutional crisis.
If Trump has a request from a governor to send in troops, there is no question over the legality of the deployment, at least at a federal level.
But to move in military force without a governor's request, Trump has to show that the people of the state do not have the basic rights of the Constitution enforced as they are entitled to, or that an 'insurrection, domestic violence, unlawful combination, or conspiracy' obstructs federal law.
If a state governor or attorney general goes to court to oppose the deployment of federal troops, they would argue that the protests and the violence do not deprive people of their constitutional rights in a way that cannot be dealt with by state authorities.
Trump would have to show that the state authorities are failing to give people 'equal protection,' the crucial clause in the Constitution which means that laws cannot be unfairly enforced.
The first clash would be in front of a federal district judge.
That clash would inevitably have to reach the Supreme Court for settlement if one side or the other does not back down.
It would then become a multi-faceted constitutional question with little precedent in this or the last century.
It raises questions of states rights; the meaning of equal protection; the extent of First Amendment rights to protest and who decides what the limits of those rights are; and what the Founders meant about how a president can decide to act in an emergency.
HAVEN'T PRESIDENTS SENT IN TROOPS WITHOUT PERMISSION BEFORE?
Yes - repeatedly, but not with clear parallels to Trump's threat.
The most recent examples were Eisenhower and JFK who used federal troops in the south on three occasions during the civil rights era.
Each time they were used to enforce desegregation, first in Little Rock in 1957, then in 1962 in the aftermath of the Ole' Miss Riot, where pro-segregationists clashed with federal forces.
1957: Nine black students - the Little Rock Nine - are escorted into an Arkansas high school by the National Guard on the orders of Dwight Eisenhower
1963: Alabama governor George Wallace, third from left, makes his 'Stand in the Schoolhouse Door' by refusing to admit two black students to the University of Alabama - sparking a stand-off which prompted John F. Kennedy to intervene by taking over the state's National Guard
Both presidents did so by citing the clear violation of the equal protection clause in the Constitution represented by segregation, and each deployment was to one state at a time.
No 20th century president ever deployed troops across multiple states without requests from governors, as happened in 1968 when troops were used in Detroit, Chicago and series of other riot-hit cities, all when governors became overwhelmed.
The last time a widespread deployment happened without governors' permission was in 1894 when Grover Cleveland used federal troops to break the Pullman Strike, which was paralyzing railroads.
But he started by getting a federal injunction against the strike, meaning it was clear what legal rights he was enforcing with federal troops, even if the governor of Illinois - the center of the strike - did not ask for the troops to be deployed, or the governors of the other states where troops broke strikes and took control of railroad facilities.
Additionally, no state challenged the invocation of the act.
Trump would be the first president to try to deploy troops in the face of states going to court to stop him.
COULD TRUMP BE STOPPED FROM USING THE ACT?
Yes - but it could be difficult to stop him in advance.
A federal judge would have to issue an injunction against the deployment, which would be appealed to the Supreme Court.
Courts have historically been very reluctant to review a president's military declarations, said law professor Robert Chesney of the University of Texas.
Beyond that, it would ultimately be up to voters to remove the president at the next election if they disapprove of his use of the Act.
'Historically, the real checks on abuse of these authorities have been political,' said Vladeck, the law professor.
But this time might be more complicated - an injunction against deployment is a real possibility if a federal judge is being asked by a governor to stop a troop deployment because the governor claims it is unconstitutional.
That would send it to the Supreme Court and until it is resolved there, the deployment is likely to stay on hold.
The case would center on whether the Founders really wanted a president to be able to unilaterally intervene in the day-to-day policing of their states - over the objection of those states.
SO WHAT MIGHT HAPPEN AT THE SUPREME COURT?
A clash between a state - and probably groups of states - and Trump would have to go to the Supreme Court unless one or other backs down.
The judges are a 5-4 conservative majority, with conservatives who say their key loyalty is to interpreting the Constitution as closely as they possibly can to the intention of the framers who wrote it.
That would put two questions at the heart of it:
On one side states might well argue that the founding fathers wanted federal government kept out of states' affairs as much as possible, that the Articles of Confederation make that clear, and that the violence in their cities does not meet the high standards set for using the federal military.
They would also be likely to argue a practical point - that states have not had a chance to decide on whether to ask for federal help, or if they have, have decided against it.
And they would also be likely to claim that the 10th Amendment to the Constitution puts 'police' powers primarily in the hands of the states.
Trump's case would center on the idea that the states could no longer guarantee the fundamental rights to life and liberty for the people of their cities, so it's up to the federal government to step in.
He would have to argue that the founders' proclamation of equal protection is the key to his actions.
And he would have to argue that military action assists people's right to protest under the First Amendment.
Then it would be up to the justices in probably the most consequential decision since Bush v Gore in 2000.
COULD THE MILITARY DISOBEY TRUMP?
Quite possibly, yes.
The military swear an oath to the Constitution, not to the president, and acknowledge him as commander-in-chief. They have a duty to follow lawful orders.
If a federal judge issued an injunction again Trump's order, the military would be expected to comply.
They would then have to wait for the outcome of the case.
The situation could vary state by state. Trump would order the military in to each state, forcing each state which objects to go to court and seek an injunction. There could be a patchwork of deployments.
And inside the Pentagon, lawyers would have to work out what the rules are and whether Trump's orders are lawful.
OTHER TIMES TROOPS QUELLED RIOTS
Troops have been called in to help deal with violent unrest repeatedly since World War II - and even during it.
In 1943 FDR acted when the governor of Michigan asked for military help as Detroit was racked by racial violence.
As social unrest gripped the nation in 1968, Johnson had to send for federal troops to put down three further riots in Washington, Baltimore and Chicago.
The rioting followed the assassination of Martin Luther King Jr. on April 4, 1968 in a wave of violence which reached dozens of US cities.
Johnson was able to deploy troops in Washington without invitation, as commander-in-chief of the District of Columbia's national guard.
In Baltimore and Chicago, the respective local leaders - governor Spiro Agnew of Maryland, the future vice president, and mayor Richard Daley of Chicago - requested Johnson's help to put down the riots.
In the most recent case, president George H.W. Bush sent federal troops to Los Angeles during the Rodney King riots in 1992.
Military units were deployed at the request of California governor Pete Wilson after the violence which broke out when four cops were acquitted of beating King.
1992: A man burns an American flag during the Rodney King riots in Los Angeles, the last time that a president - George H.W. Bush - invoked the Insurrection Act
Other uses of the Act
Having lobbied for the Insurrection Act in 1807, Jefferson was the first to use it the following year to enforce a trade embargo during the Napoleonic Wars.
Jefferson declared New York's Lake Champlain on the Canadian border to be in insurrection because of its role in smuggling, allowing him to enforce the blockade.
In addition to riots and civil rights clashes, presidents have dispatched federal troops to combat a variety of strikes and other brief episodes of unrest.
In 1989, George H.W. Bush sent troops to keep the peace in the Virgin Islands after looting in the wake of Hurricane Hugo.
His son George W. Bush considered sending troops to New Orleans in the wake of Hurricane Katrina in 2005, but eventually decided against.
The Bush White House's concerns about the legality of such a move prompted the 2007 amendment which specifically mentioned natural disasters.
There have been other occasions where the military was deployed under different laws or where the mere threat of sending troops was enough to restore calm.
Richard Nixon ordered the military to keep mail services running during a postal strike in 1970, citing the 1932 Economy Act rather than the Insurrection Act.
In 1987, Ronald Reagan authorized his Secretary of Defense to call up the National Guard to quell an Atlanta prison riot, but the troops did not prove necessary.