In a statement, Senate Intelligence Committee chairman Richard Burr, R-N.C., cited a New York Times op-ed published Thursday, after Brennan’s security was revoked, in which Brennan wrote that Trump’s claims of no collusion were "hogwash," saying the only remaining questions were whether the collusion amounted to a criminal conspiracy and whether the Trump team obstructed justice in order to cover up the collusion Brennan alleged.
Burr said that if in fact Brennan had information that proved the Trump campaign colluded with a foreign power, he should have provided that information to special counsel Robert Mueller, rather than writing about it in a newspaper.
Burr also asked that if Brennan had had direct knowledge of collusion during his CIA tenure, he should have included it in the intelligence community’s 2017 assessment of Russian interference, released just before Brennan resigned. If Brennan learned information after he left office, Burr said it would constitute an intelligence breach.
"If, however, Director Brennan’s statement is purely political and based on conjecture, the president has full authority to revoke his security clearance as head of the Executive Branch," Burr’s statement continued.
A spokesperson for Burr did not respond to a follow-up question about whether Brennan said or did anything before his clearance was revoked that led Burr to believe it should be revoked.
Brennan has been one of the more outspoken former members of the intelligence community – though far from the only one – in criticizing the president, often addressing the president directly over Twitter.
In the White House’s own announcement of his security revocation, press secretary Sarah Sanders accused Brennan of demonstrating "erratic behavior" and specifically cited testimony Brennan gave to Congress last year in denying that the so-called Steele dossier was a factor in the intelligence community's ultimate conclusion regarding Russia's interference in the 2016 election.
But she did not present any evidence that Brennan has actually ever mishandled classified information.
Back on the Hill, Sen. Lindsey Graham, R-S.C., defended the president, saying it was Brennan who had overstepped.
"Mr. Brennan has gone way over the line in my view and I think restricting his clearance, pulling his clearance makes sense to me," he said.
Sen. John Cornyn, R-Tex., told reporters Thursday that he wasn’t sure it was necessary for any former intelligence community employees to maintain their clearance "unless there is some justification not to."
Asked Wednesday for their thoughts, Sens. John Kennedy and Richard Shelby also deferred to presidential authority and focused on Brennan's faults.
"I don't see why he would need a security clearance. I really don't. And I don't think he's qualified to have one," Kennedy said, calling Brennan a "butthead."
"I don't see anything wrong with that. I don't know why they give them security clearances anyway other than maybe a transition period," Shelby added.
One Republican who bucked the party line was Sen. Susan Collins, R-Me., who said she disagreed with Brennan’s statements but also disagreed with the president’s decision.
"I believe that John Brennan has acted in far too politically a role since he left the CIA. Nevertheless I do not see the grounds for revoking his security clearance, unless there was some disclosure of classified information of which I am unaware," she said.
Senate Democrats were much more openly critical.
"I think it is pretty clear this is a president who goes out of his way to punish his political adversaries. And just really haven’t seen anything like this before," Sen. Martin Heinrich, D-NM, said.