John Brennan is pissed.

The former CIA director under President Obama, and the architect of the bin Laden raid, sat down with host Bill Maher on Friday night’s Real Time to vent about President Trump, who last week took it upon himself to revoke his security clearance. In a statement delivered by press secretary Sarah Huckabee Sanders, Trump pointed to Brennan’s “frenzied commentary” and “unfounded and outrageous allegations” as the reason for the revocation—without, of course, getting into any specifics.

Brennan, who currently serves as an MSNBC analyst, has been very critical of Trump’s cozy relationship with Vladimir Putin, branding the president’s ring-kissing during their Helsinki summit “nothing short of treasonous.”

“There are two principal reasons why I used that term,” Brennan explained to Maher of the “treasonous” comment. “One, I think I exhausted all the other adjectives in the English language to describe Donald Trump’s failures to fulfill his responsibilities as president of the United States. And two, I saw him on that stage in Helsinki failing to be able to say to the world and to Vladimir Putin that Russia tried to interfere in our election, that it never should have happened and it never should happen again, and if it does Russia is going to pay some very severe consequences as a result, but he didn’t do that.”

He went on to describe how unique the revocation was. “I didn’t ask to keep my security clearances—former directors don’t do that. We keep those clearances because sometimes, those in government want to avail themselves of our experience, our expertise, our knowledge about certain issues,” Brennan said. “This is the first time in 38 years that I haven’t had a security clearance, and the basis for the revocation is bogus. Mr. Trump and the administration didn’t adhere even to the process that they reaffirmed last year, and the politicization of security clearances, either the granting or the revocation, is a real threat to our national security.”

The 62-year-old Jersey native blamed Senator Rand Paul (R-Ky.) for being “the one that put this idea in Donald Trump’s head,” even though, according to Brennan, “Rand Paul has never served on the intelligence committee. He knows not of what he speaks, but yet he has this impression that I’m ‘monetizing’ security clearances, so he continues to spout out on these issues.”

“But again,” he continued, “I believe very strongly in the principle that national security is one of the most sacred and solemn professions in this government, and every American citizen deserves to have national security professionals—intelligence professionals—who are not going to be politicized, and no president ever should take that capability away from them.”

Later on, Maher claimed that Trump’s presidency is “the third great crisis in American history” behind the Revolutionary War and the Civil War, before asking Brennan if he agreed with that ranking.

“I would,” said Brennan. “And I think it’s going to get worse before it gets better, because don’t forget: Donald Trump has the authority of the president of the United States in his hands, in terms of what he can do domestically here and as well as what he can do internationally to try to distract attention, whether or not he’s going to try to pursue some type of foreign adventure, military or otherwise. But fundamentally though, what he’s doing to this country: he’s dividing us.”