Tonight, PBS stations across the U.S. will premiere “Plot to Overturn the Election,” a collaboration between ProPublica and Frontline. (The documentary will also appear at pbs.org/frontline.) “Plot to Overturn the Election” examines the roles and impact of key members of the movement to spread the belief that the 2020 U.S. presidential election was rigged. The documentary also explores how members of the movement helped launch and fund the audit of Arizona’s vote count and how they are working to influence future elections, in part by supporting secretary of state candidates who share their views that America’s voting systems are irredeemably corrupt.

Correspondent A.C. Thompson, along with reporters Doug Bock Clark, Alexandra Berzon and Kirsten Berg, obtained new information that helps explain why two-thirds of Republicans believe President Donald Trump won the 2020 election. In the coming weeks, ProPublica and Frontline will publish stories that further examine the movement’s past and ongoing efforts to find evidence of election fraud.

Part of the Frontline and ProPublica project focuses on a group that gathered in the weeks after the 2020 election on a South Carolina plantation owned by conservative defamation attorney Lin Wood. Using the property as a temporary headquarters, a team of lawyers and cybersecurity experts gathered and synthesized what they claimed was evidence of election fraud. This group, which included Michael Flynn, the retired three-star Army general and former national security adviser to Trump, and Patrick Byrne, the former CEO of Overstock.com, became a key originator of the since-discredited idea that foreign communist governments had hacked voting machines made by Dominion Voting Systems. The belief was central to justifying the efforts of Trump and his allies to reverse the results of the election.

The reporting on the group’s activities draws on more than a thousand private emails, photos and videos, hundreds of text messages and dozens of hours of audio recordings, none of which have been previously reported on.

“It was almost like finding a key to understanding, you know, why much of the country believes that the election was stolen,” Clark tells Thompson in the documentary.