The Trump campaign’s alleged collusion with the Russian government in the 2016 U.S. presidential election has become the defining scandal of the administration so far. This report lays out the overwhelming evidence of that collusion, exploring its underpinnings going back decades to create a cohesive explanation for how—and why—the Trump campaign and the Kremlin worked together to install Trump in the White House.

A new brief from the Center for American Progress Action Fund’s Moscow Project shows that, based on public reporting and indictments by special counsel Robert Mueller, there are at least 251 known contacts between Trump’s team and Russia-linked operatives during the campaign and transition, including at least 37 meetings.