President Donald Trump cautioned former CIA Director John Brennan on Monday that going to court to get back his revoked security clearance will make it “very easy” to obtain “all of his records” for taxpayers to see his role in the Russia collusion scandal.

“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 not only the poor job he did, but how he was involved with the Mueller Rigged Witch Hunt. He won’t sue!” Trump tweeted.

Trump revoked Brennan’s security clearance August 15 after the former CIA director “leveraged his status as a former high-ranking official with access to highly sensitive information to make a series of unfounded and outrageous allegations” about the Trump administration.

The president also insisted that “any benefits that senior officials might glean from consultations” with Brennan (pictured above right) “are now outweighed by the risks posed by his erratic conduct and behavior.”

Brennan, now a national security analyst for NBC and MSNBC, has made no secret of his bitter disdain for Trump since leaving the CIA, calling the president a “traitor” and a “tyrant.” Trump’s performance during his controversial press conference with Russian President Vladimir Putin in Helsinki, Finland, was “nothing short of treasonous,” Brennan said in a July 16 tweet.

The former CIA director threatened to pursue legal action against Trump after losing his security clearance, vowing Sunday on NBC News’ “Meet the Press” that he’d “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.

“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.

The president is also reviewing the security clearances of other former top intelligence and law enforcement officials, including former Director of National Intelligence (DNI) James Clapper, former FBI Director James Comey, former national security adviser Susan Rice, former National Security Agency (NSA) Director Gen. Michael Hayden, former FBI Deputy Director Andrew McCabe, former Associate Deputy Attorney General Bruce Ohr, former FBI Chief of the Counterespionage Section Peter Strzok, and former FBI lawyer Lisa Page.

All of them, except Hayden, who worked for President George W. Bush, were appointed by President Barack Obama.

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Related: Clapper Admits Brennan’s Anti-Trump ‘Rhetoric’ Has ‘Become an Issue’

“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,'” Trump added Monday on Twitter.

Clapper said Sunday on CNN’s “State of the Union” that Brennan’s “rhetoric” has “become an issue in and of itself. I think John is subtle like a freight train, and he’s going to say what’s on his mind.”