Russians not only affected the outcome of the 2016 presidential election — they decided it, says James Clapper, who served as the director of national intelligence in the Obama administration, and during the 2016 vote.

“To me, it just exceeds logic and credulity that they didn’t affect the election, and it’s my belief they actually turned it,” he told the PBS NewsHour anchor Judy Woodruff on Wednesday.

Clapper, who chronicles his life and career in his new book, “Facts and Fears: Hard Truths From a Life in Intelligence,” said Russians are “are bent on undermining our fundamental system here. And when a foreign nation, particularly an adversary nation, gets involved as much as they did in our political process, that’s a real danger to this country.”

His comments come amid reports that the FBI used an informant while the bureau investigated possible ties between Russia and Trump’s 2016 campaign.

“That would be one of the biggest insults that anyone’s ever seen,” Trump told reporters Tuesday, calling the reports ‘spygate’ on Twitter. The president demanded an investigation earlier this week into whether the FBI or Department of Justice infiltrated or surveilled his campaign.

Clapper called those accusations “distorted.” He said there is a “a big gulf between a spy in the traditional sense — employing spycraft or tradecraft — and an informant who is open about … who he was and what the questions he was asking.”

“The important thing was not to spy on the campaign but rather to determine what the Russians were up to. Were they trying to penetrate to campaign, gain access, gain leverage, gain influence, and that was the concern that the FBI had? … I think they were just doing their job and trying to protect our political system.”

Other highlights from the interview: