Nevada Democratic Sen. Harry Reid appeared to accuse Donald Trump’s campaign of working directly with the Russian government to undermine the US presidential election — an explosive charge for which he provided no evidence.

In an interview with the Huffington Post published Monday, Reid said there had been a “deal” involving the Trump campaign and Russia’s election hacking.

“Someone in the Trump campaign organization was in on the deal. I have no doubt. Now, whether they told [Trump] or not, I don’t know. I assume they did. But there is no question about that,” said Reid, the outgoing Senate minority leader. “So there is collusion there, clearly.”

The Huffington Post story does not cite proof — from Reid or anyone else — to back the claim that Russia was working directly with Trump’s campaign. This weekend, the Washington Post and the New York Times both reported that the CIA believes Russia hacked the Democratic National Committee to help elect Trump, a revelation that prompted a flurry of calls for congressional investigations on Capitol Hill. But none of the reports have gone as far as to allege that someone in Trump’s orbit was secretly collaborating with the Russian government.

Harry Reid being Harry Reid

Now, it’s certainly possible Reid knows something we don’t. And in the Huffington Post interview, Reid cites the intelligence briefings he’s seen — but which haven’t been made public — to argue that the members of the Electoral College should think twice before backing Trump.

“What I say to somebody that is pledged to Donald Trump is, ‘Be fair. Be fair,’” Reid said. “This is a tremendous responsibility that you have to do the right thing.”

Moreover, it’s not ridiculous to be wary of the relationship Trump’s inner circle has with Moscow. It’s not just that the CIA has concluded Russia wanted to help Trump; over the course of the campaign, close connections repeatedly emerged between members of his campaign and Russia, including key players such as:

Paul Manafort , Trump’s former campaign manager, worked in pro-Russia politics in Ukraine and nabbed “some lucrative side deals with Russian and Ukrainian oligarchs,” according to the Washington Post. The FBI opened a “preliminary inquiry” into Manafort’s ties to Russia but never found released proof of collusion.

, Trump’s former campaign manager, worked in pro-Russia politics in Ukraine and nabbed “some lucrative side deals with Russian and Ukrainian oligarchs,” according to the Washington Post. The FBI opened a “preliminary inquiry” into Manafort’s ties to Russia but never found released proof of collusion. Carter Page , an ex-Trump adviser on foreign policy, was also scrutinized by the FBI under suspicion of communicating with senior Russian officials, according to the New York Times.

, an ex-Trump adviser on foreign policy, was also scrutinized by the FBI under suspicion of communicating with senior Russian officials, according to the New York Times. Trump ally Roger Stone admitted to having a backchannel to WikiLeaks during the campaign, though not the federal government. (Stone declined ever having any contact with the Russian government.)

All of that said, Reid’s claim should be met with a healthy dose of skepticism — for the obvious reason that we don’t have any evidence that it’s true. Earlier on Monday, Rep. Eric Swalwell, a Democrat from California, told me that he thought the House should investigate whether Trump’s team had been in touch with the Russians. But Swalwell acknowledged that there was no evidence to that effect.

Reid is also something of an unreliable narrator. In 2012, he falsely claimed to have seen Mitt Romney’s tax returns, and said that they showed Romney hadn’t paid taxes in more than a decade. Reid has since acknowledged lying about that charge, but hasn’t apologized.

"Romney didn't win, did he?" Reid said. “I don’t regret that at all.”