Yale historian lays out 50 reasons to suspect Trump has been corrupted by Russia
Trump abruptly cancelled a meeting with Russian President Vladimir Putin planned for the G20 summit. (AFP/File / Brendan Smialowski)

A Yale historian laid out 50 pieces of publicly available evidence that he believes shows President Donald Trump has been compromised by Russia and its president.

Timothy Snyder has been warning since before Trump's election that his ties to Russia and his disregard for the law and political norms posed a danger to U.S. democracy, and he tweeted out some of the evidence from his new book The Road to Unfreedom laying out a case against the president.

Attorney General William Barr is putting the finishing touches on his redacted version of special counsel Robert Mueller's report, but Snyder said there's ample evidence, dating back to at least 1984, that Trump has engaged in illegal and compromising activity with Russian mobsters and spies.

“It’s literally impossible to understand Trump without Russia,” Snyder told The Chronicle of Higher Education.

Snyder gathered evidence that Russian gangsters began laundering money through Trump Tower in the 1980s, and the future president visited Moscow in 1987, where he was almost certainly targeted by spies, after he was courted by Soviet diplomats.

Trump started attracting Russian investors a decade ago, and he publicly sought a closer relationship to Vladimir Putin and conducted business in Moscow -- which his attorney pleaded guilty to lying about -- up through the 2016 campaign.

Barr claims that Mueller was unable to find evidence of criminal wrongdoing against the president, but Syder says Trump clearly benefitted from Russian efforts to tip the election to him, after cultivating ties to the former reality TV star for years.

“Russia obviously interfered in U.S. elections,” he said.