Donald Trump would have been on his way to losing the 2016 election without help from Vladimir Putin and the Russians, former Director of National Intelligence James Clapper claims.

Clapper has been vocal about Russia’s role in the election as he promotes his new memoir, Facts and Fears: Hard Truths From a Life in Intelligence. As The Daily Beast noted, Clapper is adamant that it was Russia’s actions in interfering in the election that swung the race to Donald Trump.

“Of course the Russian efforts affected the outcome,” he wrote (via The Daily Beast). “Surprising even themselves, they swung the election to a Trump win. To conclude otherwise stretches logic, common sense, and credulity to the breaking point.”

Russia is accused of launching a multi-pronged campaign to help elect Trump, one that included hacking emails from Hillary Clinton’s campaign manager and from the Democratic National Committee and sharing them through WikiLeaks. Russia is also accused of launching a disinformation campaign across social media, spreading divisive and sometimes outright false political messages on Facebook, Twitter, and Reddit.

Clapper said the American intelligence community concluded that the campaign was made at the direct order of Vladimir Putin, who wanted Donald Trump to win the election to destabilize the United States.

“We showed unambiguously that Putin had ordered the campaign to influence the election… and how the entire operation had begun with attempts to undermine U.S. democracy and demean Secretary Clinton, then shifted to promoting Mr. Trump when Russia assessed he was a viable candidate who would serve their strategic goals,” he wrote.

Others take a different assessment on why Donald Trump won the 2016 election despite the final polls leading up to Election Day showing him far behind Hillary Clinton. Poll aggregator Nate Silver wrote on his site FiveThirtyEight that Clinton likely would have won were it not for the October 28 letter from FBI Director James Comey announcing a new leg in the investigation of her email case. Some of Clinton’s emails showed up on a device belonging to Anthony Weiner in the FBI’s investigation of him, and Comey said he felt bound to alert Congress that they were sorting through them.

Former intell chief James Clapper: "Of course the Russian efforts affected the outcome. Surprising even themselves, they swung the election to a Trump win. To conclude otherwise stretches logic, common sense, and credulity to the breaking point"https://t.co/UDqsDsPfLE — Michiko Kakutani (@michikokakutani) May 23, 2018

Though the FBI announced just days later that there were no classified emails found and that it would not change the conclusion that Clinton committed no crime, Nate Silver believes that the damage was done.

“The real story is that the Comey letter had a fairly large and measurable impact, probably enough to cost Clinton the election,” he wrote. “It wasn’t the only thing that mattered, and it might not have been the most important. But the media is still largely in denial about how much of an effect it had.”

Donald Trump has repeatedly denied that he colluded with Russia.