The January 6 select committee showed on Thursday that Mike Pence withstood an intense pressure campaign from Donald Trump and his allies to overturn the results of the 2020 presidential election.

Trump’s advisers repeatedly tried to convince Pence to disrupt the congressional certification of Joe Biden’s victory on January 6, even after they themselves acknowledged that there was no constitutional basis for the vice-president to do so.

Pence ultimately refused to interfere with the certification process, despite facing threats to his personal safety from Trump’s supporters who stormed the Capitol. But if Pence had acquiesced to Trump’s demands, the US could have faced an unprecedented constitutional crisis, the committee warned on Thursday.

“We’re fortunate for Mr Pence’s courage on January 6,” said Bennie Thompson, the Democratic chair of the committee. “Our democracy came dangerously close to catastrophe.”

Thompson’s warning was echoed by Michael Luttig, a retired federal judge who served as an advisor to Pence in the weeks after the 2020 election. Luttig argued that, if Pence had tried to overturn the results of the election, that effort would have threatened the very foundation of American democracy.

“That declaration of Donald Trump as the next president would have plunged America into what I believe would have been tantamount to a revolution within a constitutional crisis,” Luttig said.

The Trump team’s legal efforts to overturn the election results were spearheaded by conservative lawyer John Eastman, the committee heard Thursday. Eastman tried to convince Pence and his advisors that the vice-president had the authority, under the Electoral Count Act of 1887, to reject the results. Luttig summarily rejected that theory on Thursday, joining a loud chorus of constitutional experts who had already dismissed Eastman’s idea.

“There was no basis in the Constitution or laws of the United States, at all, for the theory espoused by Mr Eastman. At all. None,” Luttig said. He added, “I would have laid my body across the road before I would have let the vice-president overturn the 2020 presidential election on the basis of that historical precedent.”

According to Pence’s former counsel, Greg Jacob, even Eastman himself acknowledged that such a strategy would not withstand legal scrutiny. Eastman told Jacob that he believed the supreme court would reject the theory in a unanimous vote of 9 to 0.

And yet, Trump and his allies continued to pursue their unconstitutional strategy. The committee shared new footage Thursday showing January 6 insurrectionists threatening the vice-president for refusing to block the certification, as rioters chanted, “Hang Mike Pence!”

Instead of offering support to his endangered vice-president, Trump escalated his pressure on Pence. At 2.24pm, Trump tweeted, “Mike Pence didn’t have the courage to do what should have been done to protect our country and our Constitution, giving states a chance to certify a corrected set of facts, not the fraudulent or inaccurate ones which they were asked to previously certify. USA demands the truth!”

Committee member Pete Aguilar, who took a lead role in questioning Jacob and Luttig at the Thursday hearing, said that immediately after Trump sent his tweet, the crowds in and around the Capitol surged, and Pence was evacuated.

“Make no mistake about the fact that the vice-president’s life was in danger,” Aguilar said.

In light of the serious threats Pence faced on January 6, many viewers of the hearing marveled at the fact that he ultimately followed through with certifying the election, ensuring the transfer of presidential power.

“Had Pence not certified the election, there’d likely be violent protests in the streets,” Alyssa Farah Griffin, Trump’s former communications director, said on Twitter. “Lame duck Trump would undoubtedly try to use the military to quell unrest. You’d have general officers refusing orders. The republic would be in crisis.”

Instead, Congress stayed in session until the early hours of 7 January to oversee the counting of electoral college votes and make Biden’s victory official.

In the year and a half since the insurrection, lawmakers have taken steps to guarantee that a future vice-president cannot ignore the will of the people. A bipartisan group of senators is working to reform the Electoral Count Act, and they announced last week that they had reached a general agreement on language clarifying the vice-president’s role to be entirely ministerial during the counting of electoral college votes.

The alarming testimony from members of Pence’s inner circle underscored the immense importance of those senators’ work, while revealing just how close the US came to an even larger disaster on January 6.

Thompson chose to close out the Thursday hearing with a stark warning to the entire country: although the system of American democracy held this time, that does not guarantee it will survive the next threat.

“There are some who think the danger has passed, that even though there was violence and a corrupt attempt to overturn the presidential election, the system worked,” Thompson said.

“I look at it another way. Our system nearly failed and our democratic foundation destroyed but for people like you.”