Republicans looking to defend President Donald Trump could have fewer arrows in their quiver after a veteran US diplomat and the National Security Council's former top Russia expert gave evidence before the House Permanent Select Committee on Intelligence.
The atmosphere at Friday's hearing, the last of seven which committee chair Rep. Adam Schiff, D-California has held as part of the House of Representatives' impeachment inquiry into Mr Trump, was perhaps more subdued than the six which preceded it, but the testimony offered by both Dr Fiona Hill – formerly the Trump White House's top Russia adviser – and Mr Holmes, the third-ranking official at America's embassy in Kiev, was no less consequential.
Over the course of seven hours, Dr Hill and Mr Holmes methodically dismantled conspiracy theories which have made frequent appearances in Republican talking points during the first three years of Mr Trump's presidency.
Such was the precision with which Dr Hill, a Harvard-educated Russia expert and the author of a biography of Russian president Vladimir Putin, used her opening statement to eviscerate some of the favourite talking points of the committee's ranking member, California's Devin Nunes, that he tried blunting the impact of her words in his own opening statement.
"It's possible for two nations to engage in [election] meddling at the same time," said Mr Nunes, who noted for Dr Hill's benefit that in 2018, the then-Republican-controlled House had compiled a report which acknowledge to some degree what the US intelligence community had long concluded, namely that Russia had interference in the 2016 election.
Prepared under the leadership of Mr Nunes, who chaired the intelligence committee until Democrats regained control of the House this year, the report was widely criticised for attacking the US intelligence community's conclusion as poorly reasoned, and for indulging baseless conspiracy theories.
It was those conspiracy theories which Dr Hill proceeded to debunk in her opening statement.
"Based on questions and statements I have heard, some of you on this committee appear to believe that Russia and its security services did not conduct a campaign against our country– and that perhaps, somehow, for some reason, Ukraine did. This is a fictional narrative that has been perpetrated and propagated by the Russian security services themselves," Dr Hill said.
"The unfortunate truth is that Russia was the foreign power that systematically attacked our democratic institutions in 2016. This is the public conclusion of our intelligence agencies, confirmed in bipartisan Congressional reports," she continued. "It is beyond dispute, even if some of the underlying details must remain classified."
But it wasn't just Dr Hill who poured cold water all over Mr Nunes' pet theories.
Another tale he and other Republicans have spun since 2017 is that of the "black ledger," a document seized from the headquarters of Ukraine's pro-Russia Party of Regions after the fall of former president Viktor Yanukovych's government.
The ledger has been a bete noire for Republicans since the summer of 2016, when its public release revealed that then-Trump campaign manager Paul Manafort had received 22 off-the-books payments from Yanukovych's party totaling $12.7 million.
The ledger's exposure forced Mr Manafort to resign from the Trump campaign, and was used as evidence when he was later indicted in a Virginia court for tax fraud.
Though Manafort was convicted in an American court by an American jury, Mr Nunes and other Republicans have frequently claimed that the ledger itself was part of a Ukrainian disinformation campaign meant to sabotage Mr Trump by hurting Mr Manafort.
It was that theory which Mr Nunes had in mind when he began questioning Mr Holmes.
Asked by Mr Nunes if he'd heard of the ledger, Holmes replied: "I have."
Encouraged, the Republican continued.
"The black ledger – is that seen as credible information?" he asked.
Mr Nunes was visible startled by Holmes reply of "yes" -- a reply he repeated when the congressman asked the question again.
Mr Holmes' repetition of his first affirmative answer further discombobulated Mr Nunes, who then questioned the veteran diplomat about a false claim concerning whether former special counsel Robert Mueller -- who had used the ledger to secure an indictment of Manafort -- had found it credible.
"Bob Mueller did not find it credible. Do you dispute what Bob Mueller's findings were? They didn't use it in the prosecution or in the report," he asked.
Mr Holmes replied: "I'm not aware that Bob Mueller did not find it credible. I think it was evidence in other criminal proceedings. Its credibility was not questioned in those proceedings, but I'm not an expert on that."
Speaking to The Independent after Thursday's hearing, Representative Raja Krishnamoorthi praised Dr Hill's willingness to stand up for the facts.
"I think she's very authoritative on these issues, she's very strong, and she's convincing," said Krishnamoorthi, an Illinois Democrat.
"I hope that people at home who are watching realise that in listening to her, we can put an end to this nonsense that we hear from the other side -- that DNC server theory, Biden/Burisma, and all the other crackpot theories out there," he said.
Rep Dean Phillips, D-Minnesota, expressed regret that today's modern media landscape makes it harder for all Americans to operate with a shared reality.
"I grew up in an era where the national networks broadcast the news, and the next morning everyone would debate the news, and now we're debating opinion," he said, but added that the fact-based testimony of people like Dr Hill and Mr Holmes gave him hope that a return to a shared set of facts among both parties was possible.
"It's refreshing and we need more of that, but we also need to encourage and invite our country to return to that intention -- to argue the facts, not only share opinion," he said.