Intelligence officials on Sunday expressed concern that ex-CIA Director John BrennanJohn Owen BrennanClinton lawyer's indictment reveals 'bag of tricks' Still in the game: Will Durham's report throw a slow curveball at key political players? UFOs are an intriguing science problem; Congress must act accordingly MORE has waded too far into politics with his vehement criticism of President TrumpDonald TrumpTrump takes shot at new GOP candidate in Ohio over Cleveland nickname GOP political operatives indicted over illegal campaign contribution from Russian national in 2016 On The Money — Dems dare GOP to vote for shutdown, default MORE, days after the administration drew critical fire for revoking Brennan's security clearance.
"I think John is subtle like a freight train, and he's going to say what's on his mind," James ClapperJames Robert ClapperAfghanistan disaster puts intelligence under scrutiny Domestic security is in disarray: We need a manager, now more than ever Will Biden provide strategic clarity or further ambiguity on Taiwan? MORE, a former director of national intelligence, said on CNN's "State of the Union."
Clapper is among the former intelligence officials whose clearances are under review by the White House. Each individual has been vocally critical of the president since he took office, prompting speculation that the move is meant to be retaliatory.
"I think, though, that the common denominator among all of us that have been speaking up, though, is genuine concern about the jeopardy or threats to our institutions and values, and although we may express that in different ways," Clapper said. "And I think that's what this really is about."
"But John and his rhetoric have become, I think, an issue in and of itself," Clapper added.
Trump's national security adviser, John Bolton, and a number of former intelligence officials appeared on Sunday shows to discuss the fallout of Trump revoking Brennan's clearance. Only Bolton defended the move, while other former officials worried that the revocation would have a chilling effect on free speech.
However, Clapper and retired Adm. Mike Mullen voiced concerns that Brennan has made himself the story in what has traditionally been an apolitical arm of government.
"John is an extraordinary servant of the country, but I think he has been incredibly critical of the president and I think that has put him in a political place which actually does more damage for the intelligence community, which is apolitical, even as he's retired," Mullen said on "Fox News Sunday."
Mullen, who served as the chairman of the Joint Chiefs of Staff from 2007-2011, still took issue with Trump pulling Brennan's clearance.
"I do worry about the fact that that, one, John is now in the political arena and, two, at the same time, I don't agree with the president pulling it," he said. "I think I am concerned about the whole issue of free speech. And as long as John is not revealing classified information that he shouldn't, then I certainly think he has a right to speak."
Past administration officials keep security clearances, in part, to offer counsel and advice to their predecessors. The clearances can also be valuable in post-government work, as companies can look to hire people with top security clearances for consulting work.
Bolton, who served in the George W. Bush administration and later emerged as a fervent critic of the Obama administration, agreed that "political disagreement alone" is not enough to warrant revoking security clearances.
Instead, Bolton argued on ABC's "This Week" that Brennan has blurred the lines between "intelligence and policy." However, he was unable to provide evidence that Brennan disseminated or abused his access to classified information.
"In terms of what he said since he left, I think a number of people have commented that he couldn’t be in the position he’s in of criticizing President Trump and his so-called collusion with Russia unless he did use classified information. But I don’t know the specifics," Bolton said.
"What I do know is when he was director of CIA, I was very troubled by his conduct, by statements he made in public, and by what I thought was his politicization of the intelligence community," he added.
Michael Hayden, a former official whose clearance is under review, said the politicization of the intelligence community goes beyond Brennan's commentary on the Trump administration.
"Our complaint is not just about (revoking Brennan's clearance). It's about the whole tone, tenor and behavior of the administration," Hayden said on CNN.
Trump has regularly attacked the Department of Justice (DOJ), the FBI and special counsel Robert MuellerRobert (Bob) MuellerSenate Democrats urge Garland not to fight court order to release Trump obstruction memo Why a special counsel is guaranteed if Biden chooses Yates, Cuomo or Jones as AG Barr taps attorney investigating Russia probe origins as special counsel MORE, often accusing them of bias and conflicts of interest without providing evidence.
Hayden, who served as CIA director for Presidents George W. Bush and Obama, warned that the relationship between Trump and the intelligence community is "dangerously close to being permanently broken."
Brennan said on NBC's "Meet the Press" that he has received an outpouring of support from former intelligence officials. More than a dozen ex-government officials have written or signed letters condemning Trump's decision to revoke Brennan's clearance.
"I don’t believe I’m being political at all," Brennan said. "I’m not a Republican, I’m not a Democrat and many members of the Congress over the years who have security clearances have spoken out rather forcefully against whoever was in the Oval Office if they weren’t from the same political party."
"So now as a private citizen they’re telling me that I shouldn’t do that?" he continued "I’m sorry, I just fundamentally disagree with that."
As Trump raises the specter of using security clearances as a political weapon, pledging to revoke the clearance of DOJ employee Bruce Ohr, Brennan said Sunday he would do whatever he could to block the president from such action, even it if means going to court.
"If my clearances and my reputation as I’m being pulled through the mud now, if that’s the price we’re going to pay to prevent Donald Trump from doing this against other people, to me it’s a small price to pay," Brennan said.