WASHINGTON — Former CIA director John Brennan said Sunday he is willing to take President Trump to court to prevent other current and former officials from having their security clearances revoked, escalating a battle over whether the president is misusing the power of his office to retaliate against opponents.
‘‘I am going to do whatever I can personally to try to prevent these abuses in the future, and if it means going to court, I will do that,’’ Brennan said in an appearance on NBC News’s ‘‘Meet the Press.’’
Brennan, who is among Trump’s most outspoken critics, had his security clearance abruptly revoked by the White House last week.
Since then, Brennan said Sunday, a number of lawyers have gotten in touch with him and offered advice on pursuing a possible injunction to prevent Trump from taking similar actions in the future.
‘‘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.
He did not immediately elaborate on what such a legal move would look like.
Asked during an appearance on Fox News Channel’s ‘‘Sunday Morning Futures’’ about a possible lawsuit by Brennan, Rudy Giuliani, Trump’s personal attorney, described it as a welcome opportunity.
‘‘I would volunteer to do that case for the president. I would love to have Brennan under oath,’’ Giuliani said. ‘‘We will find out about Brennan, and we will find out what a terrible job he did.’’
On Friday, 14 former CIA directors and deputy directors from Republican and Democratic administrations, as well as a former director of national intelligence, called Trump’s revocation of Brennan’s clearance a blatant attempt to ‘‘stifle free speech’’ and send an ‘‘inappropriate and deeply regrettable’’ signal to other public servants.
As the furor over Trump’s move has intensified, the president has showed no signs of backing down.
According to senior administration officials, the White House has drafted documents revoking the clearances of other current and former officials who Trump has demanded be punished for criticizing him or playing a role in the investigation of Russian interference in the 2016 election.
In the ‘‘Meet the Press’’ interview, Brennan also defended his previous statement denouncing Trump’s performance at a summit with Russian President Vladimir Putin in Helsinki last month as ‘‘treasonous.’’ Some of Brennan’s detractors have argued that the remark pushed his criticism of Trump into overly partisan territory.
‘‘I called his behavior ‘treasonous,’ which is to betray one’s trust and to aid and abet the enemy,’’ Brennan said. ‘‘I stand very much by that claim.’’
Brennan received some support on Sunday from Mike Mullen, a retired Navy admiral and former chairman of the Joint Chiefs of Staff, who said Trump’s threat to revoke the security clearances of those who have been critical of him is a sign that the president is ‘‘creating a list of political enemies.’’
Mullen said that while Trump has the authority to pull the security clearances of former national intelligence and other officials, his doing so is ‘‘incredibly problematic.’’
‘‘It immediately brings back the whole concept of the ‘enemies list’ under President Nixon,’’ Mullen said in an appearance on ‘‘Fox News Sunday,’’ adding that it was also reminiscent of the anticommunist crusade led by Joseph McCarthy in the 1950s.
Mullen said that he does not support Brennan being as critical of Trump as he has been but believes that the former CIA director and others should not have to fear that they will be stripped of their security clearances because of their criticism.
Former CIA director Michael Hayden, whose security clearance the White House has warned is also in danger of being revoked, said during an appearance on CNN’s ‘‘State of the Union’’ that the relationship between the president and that national security community is ‘‘dangerously close to being permanently broken.’’
Others on Sunday morning rallied to Trump’s defense.
National security adviser John Bolton backed the idea of a formal review to determine whether former officials should keep their security clearance and said Brennan may have ‘‘crossed the line.’’
‘‘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,’’ Bolton said on ABC’s ‘‘This Week,’’ but he added he has no knowledge of a specific instance.
