For much of our democracy’s history, the idea of a sitting American president refusing to concede a decisive re-election loss to his successor and instead attempting to overturn the election would’ve seemed near-unthinkable.

But it’s exactly what happened in the aftermath of the 2020 U.S. presidential election — and as tonight’s two-hour season premiere of FRONTLINE reports, when it comes to Donald Trump, the warning signs of what was coming were there all along.

Starting with its striking opening sequence, which you can watch above, Lies, Politics and Democracy shows how a big and serious lie took shape and gained potency, in plain sight, with everyone watching.

“Our film documents how Republican leaders made decisions over years that culminated in the Jan. 6 attack on Congress,” the documentary’s director, Michael Kirk, told me. “But we also discovered that the decisions made by those same leaders after the attack were even more consequential in the ongoing threat to our democracy.”

With his team, Michael has made more than 15 documentaries chronicling Trump’s impact on America’s political system, including America’s Great Divide: From Obama to Trump, Trump’s Takeover, The Choice 2020: Trump vs. Biden and Trump’s American Carnage. His newest film reveals the context and anatomy of the attack on our democracy — how it happened, who was behind it, who stood in the way and why it matters — in a way that’s unique and important.

Working with renowned journalists Tim Alberta and Jelani Cobb, Michael and his team have laid bare startling details from GOP insiders on how the indulgence of Trump’s authoritarian impulses and embrace of his rhetoric enabled his power over the American political system. They have pinpointed key moments in the evolution of the threat, including what happened after then-candidate Trump’s claim that his loss to Ted Cruz in the 2016 Iowa primary election was “rigged”; how President Trump purged the Republican party of his critics; how GOP leaders helped Trump’s false claims catch fire in the critical days and weeks after Joe Biden’s victory; and how their pattern of accommodation continued after the events of Jan. 6.

Lies, Politics and Democracy does what we so often aspire to do at FRONTLINE: providing a long view of a problem, and tracing its origins. With unique and essential clarity, the documentary shows how and why we reached a point where most Republican voters continue to believe the lie that the 2020 election was stolen.

By the end of Lies, Politics and Democracy, you will understand more deeply than ever before that this crisis is far from over.

Daniel Ziblatt, co-author of the 2018 book How Democracies Die, says in the film, “a democracy can’t survive if politicians and political parties don’t know how to lose… Sometimes, people have even said democracy is for losers. It’s a system that allows losers to come back and fight another day. And so, if the losers deny that they’ve lost, the system can’t endure.”

Lies, Politics and Democracy is supported by Preserving Democracy, a public media initiative from The WNET Group. The documentary will be available to watch in full at pbs.org/frontline and in the PBS Video App starting tonight at 7/6c, and it will premiere on PBS stations (check local listings) and on our YouTube channel at 9/8c.

Plus: Later today we will publish dozens of extended interviews with our sources from the making of Lies, Politics and Democracy — including U.S. Rep. Adam Kinzinger (R-IL), former federal Judge J. Michael Luttig, former White House Director of Strategic Communications Alyssa Farah Griffin, and former members of Congress Mark Sanford (R-SC) and Jeff Flake (R-AZ) — as part of FRONTLINE’s ongoing Transparency Project. We hope you’ll explore them and come away with new insights.

Thank you for supporting FRONTLINE’s mission of bringing you tough, fair, independent journalism that illuminates the most critical issues of our time.