John Brennan lawsuit an empty threat, Donald Trump says

“Bring it on.”

Both President Trump and top attorney Rudolph W. Giuliani wrote words to that effect Monday at former CIA Director John O. Brennan, saying they hope he sues him over the revocation of his security clearance

The president said Mr. Brennan won’t follow through on the threat because of how easy it would be to discredit him and prove he had been in cahoots with special counsel Robert Mueller.

“I hope John Brennan, the worst CIA Director in our country’s history, brings a lawsuit. It will then be very easy to get all of his records, texts, emails and documents to show to show not only the poor job he did, but how he was involved with the Mueller Rigged Witch Hunt. He won’t sue!” Mr. Trump tweeted.

Mr. Giuliani also took to Twitter to address Mr. Brennan.

“To John Brennan: Today President Trump granted our request (Jay Sekulow and me) to handle your case. After threatening if you don’t it would be just like Obama’s red lines. Come on John you’re not a blowhard?” the former New York mayor taunted.

During an interview on NBC’s “Meet the Press”on Sunday, Mr. Brennan said he met with lawyers to discuss courses of legal action he could pursue to push back against Mr. Trump’s clearance crackdown.

“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,” Mr. Brennan said.

The threat of a legal battle comes after a war of words between Mr. Trump and Mr. Brennan reached a fever pitch last week.

Mr. Trump revoked Mr. Brennan’s security clearance on Aug. 15 and announced that several other former Obama-era officials who have crossed the president may be stripped of their clearances. Former FBI Director James B. Corey, former FBI agent Peter Strzok and former acting Attorney General Sally Yates are also on the list.

Mr. Brennan fired back the next day in a New York Times op-ed, and said there is no question that the president is guilty of collusion.

“Mr. Trump’s claims of no collusion are, in a word, hogwash,” Mr. Brennan wrote in an op-ed published in The New York Times. “Mr. Trump clearly has become more desperate to protect himself and those close to him, which is why he made the politically motivated decision to revoke my security clearance in an attempt to scare into silence others who might dare to challenge him.”

The dispute has drawn in others.

Sen. Mark Warner of Virginia, the Senate Intelligence Committee’s top Democrat, said Monday evening that he has filed an amendment to the defense appropriations bill to prohibit Mr. Trump from revoking security clearances except as outlined by federal procedure.

“President Trump’s actions over the last week are beyond outrageous,” Mr. Warner said. “His tactics are reminiscent of another president who abused his office to settle scores and punish critics.”

By Monday morning, the number of former national-security officials who had signed a letter denouncing Mr. Trump for a “political litmus test” on security clearances had grown to more than 175.

“Our signatures below do not necessarily mean that we concur with the opinions expressed by former CIA Director [John O.] Brennan or the way in which he expressed them,” the letter read. “What they do represent, however, is our firm belief that the country will be weakened if there is a political litmus test applied before seasoned experts are allowed to share their views.”

Former CIA Deputy Chief of Staff Nick Shapiro shared the screenshots on Twitter of the entire statement, which was originally published Friday with only 60 signatories. It followed another joint statement put out Friday by former a dozen top members of the intelligence community accusing the president of “attempting to stifle free speech.”

Mr. Trump brushed aside that support Monday, accusing those speaking out of wanting to preserve their own security clearances, not to defend the former CIA director.

“Everybody wants to keep their Security Clearance, it’s worth great prestige and big dollars, even board seats, and that is why certain people are coming forward to protect Brennan. It certainly isn’t because of the good job he did! He is a political ’hack,’” he wrote on Twitter.

• Dan Boylan contributed to this article.