The CEOs started calling before President Trump had even finished speaking. What America’s titans of industry were hearing from the Commander in Chief was sending them into a panic.

It was Nov. 5, 2020, two days after the election, and things weren’t looking good for the incumbent as states continued to count ballots. Trump was eager to seed a different narrative, one with no grounding in reality: “If you count the legal votes, I easily win,” he said from the lectern of the White House Briefing Room. “If you count the illegal votes, they can try to steal the election from us.”

The speech was so dangerously dishonest that within a few minutes, all three broadcast television networks spontaneously stopped airing it. And at his home in Branford, Conn., the iPhone belonging to the Yale School of Management professor Jeffrey Sonnenfeld began to buzz with calls and texts from some of the nation’s most powerful tycoons.

The CEOs of leading media, financial, pharmaceutical, retail and consulting firms all wanted to talk. By the time Tom Rogers, the founder of CNBC, got to Sonnenfeld, “he had clearly gotten dozens of calls,” Rogers says. “We were saying, ‘This is real—Trump is trying to overturn the election.’ Something had to happen fast.”

For decades, Sonnenfeld has been bringing business leaders together for well-attended seminars on the challenges of leadership, earning a reputation as a “CEO whisperer.” A committed capitalist and self-described centrist, he has informally advised Presidents of both parties and spoke at Senate GOP leader Mitch McConnell’s wedding. Now he suggested the callers get together to make a public statement, perhaps through their normal political channels, D.C. industry lobbies such as the U.S. Chamber of Commerce and the Business Roundtable (BRT). But the CEOs wanted Sonnenfeld to do it; the trade groups, they fretted, were too risk-averse and bureaucratic. And they wanted to do it right away: when Sonnenfeld, who issues invitations for his summits eight months in advance in order to secure a slot on CEOs’ busy calendars, suggested a Zoom call the following week, they said that might be too late.

The group of 45 CEOs who assembled less than 12 hours later, at 7 a.m. on Nov. 6, represented nearly one-third of Fortune’s 100 largest companies: Walmart and Cowen Inc., Johnson & Johnson and Comcast, Blackstone Group and American Airlines. Disney’s Bob Iger rolled out of bed at 4 a.m. Pacific time to join, accompanied by a large mug of coffee. (Sonnenfeld, who promised the participants confidentiality, declined to disclose or confirm their names, but TIME spoke with more than a dozen people on the call, who confirmed their and others’ participation.)

The meeting began with a presentation from Sonnenfeld’s Yale colleague Timothy Snyder, the prominent historian of authoritarianism and author of On Tyranny. Snyder did not beat around the bush. What they were witnessing, he said, was the beginning of a coup attempt.

“I went through it point by point, in a methodical way,” recalls Snyder, who has never previously discussed the episode. “Historically speaking, democracies are usually overthrown from the inside, and it is very common for an election to be the trigger for a head of state or government to declare some kind of emergency in which the normal rules do not apply. This is a pattern we know, and the name for this is a coup d’état.” What was crucial, Snyder said, was for civil society to respond quickly and clearly. And business leaders, he noted, have been among the most important groups in determining whether such attempts succeeded in other countries. “If you are going to defeat a coup, you have to move right away,” he says. “The timing and the clarity of response are very, very important.”

A lively discussion ensued. Some of the more conservative executives, such as Blackstone CEO Stephen Schwarzman, wondered if the threat was being overstated, or echoed Trump’s view that late ballots in Pennsylvania seemed suspicious. Yet others corrected them, pointing out that COVID-19 had led to a flood of mail-in ballots that by law could not be counted until the polls closed. By the end of the hour, the group had come to agreement that their normal political goals—lower taxes, less regulation—weren’t worth much without a stable democracy underpinning them. “The market economy works because of the bedrock foundation of the rule of law, the peaceful succession of power and the reserve currency of the U.S. dollar, and all of these things were potentially at risk,” former Thomson Reuters CEO Tom Glocer tells TIME. “CEOs are normally hesitant to get involved in political issues, but I would argue that this was a fundamental business issue.”