Jim Obergefell and Rick Hodges both have their names on the court’s historic ruling that legalised gay marriage in the US in 2015.
Now they have banded together to oppose Ms Barrett’s nomination to the country’s highest court amid fears she and the other conservative justices could put gay marriage at risk.
Mr Obergefell sued the state of Ohio to have his marriage recognised, while Mr Hodges ran the state’s Public Health Department at the time.
Ms Barrett’s nomination was forwarded on Thursday by the Senate Judiciary Committee to the full Senate with a 12-0 vote after Democrats boycotted it in protest.
“We ask the Senate to vote no on this nomination,” said Mr Obergefell during an event to criticise her nomination.
“Judge Barrett's well-known stances on marriage equality, trans equality and other issues represent a serious risk to our civil rights and our ability to form and protect our families.”
Mr Obergefell also recalled that Justice Ginsburg had “famously advocated for full milk marriage rather than skim milk marriage for same-sex couples, with all of the attending rights and responsibilities; nothing short of full equality for all was acceptable to her.”
And he emphasised that it was important that both he and Mr Gates were united “to support that vision of full equality.”
Mr Hodges said he wanted all Americans to be “treated with full dignity and respect regardless of who they are or whom they love, and that all American families benefit equally full and fully from government services.”
“They pay for it through their taxes,” he added.
Mr Hodges was Ohio’s Health Director in 2012 when Mr Obergefell sued the state for not recognising his marriage to his critically ill husband, which was performed in another state.
The case eventually wound up in the Supreme Court in 2015 and was decided in a 5-4 ruling for Mr Obergefell.
Mr Hodges has called it a “wonderful decision” and already had his department ready to process gay marriages ahead of the court’s ruling.