updated at 3:35 p.m ET
The top Democrat on the House Oversight Committee is demanding an explanation of President Trump's decision this week to revoke the security clearance of former CIA director John Brennan
In a letter to White House Chief of Staff John Kelly, Rep. Elijah Cummings, D-Md., asked for a detailed briefing on the decision and suggested Trump may have failed to follow proper procedures.
Brennan himself also pushed back against the president's move, calling it "desperate" and "politically motivated."
The public spat highlights the increasingly partisan shadow that's been cast over national security and intelligence in the Trump era.
The administration has offered conflicting explanations for the president's decision. Trump's initial statement pointed to what the president called Brennan's "erratic conduct and behavior," a standard that Cummings challenged.
"If making 'outrageous' statements or engaging in 'wild outbursts on the Internet and television' were grounds for denying access to classified information, many of the President's top aides — indeed, perhaps even the President himself — would be swept into this unprecedented new category," the congressman wrote.
Trump later pointed to Brennan's role in investigating Russia's interference in the 2016 presidential election. Brennan helped lead that probe as CIA director in the Obama administration. Trump blames Brennan and others for planting the seeds of the special counsel's probe that has dogged his presidency for the last 15 months.
"I call it the rigged witch hunt," Trump told the Wall Street Journal. "And these people led it."
Trump said that's why he wanted to strip Brennan of his security clearance. "I think it's something that had to be done," he told the Journal.
There was no suggestion that Brennan has leaked classified information.
The White House is also reviewing the security clearance of other former officials who have been critical of the president, including former national intelligence director James Clapper, former national security agency director Michael Hayden, and former FBI director James Comey.
Former high-ranking officials typically retain their security clearance when they leave office so their successors can consult with them on sensitive issues.
In an op-ed for the New York Times, Brennan argued the decision to strip his security clearance and review others' is designed to muzzle the president's political opponents.
"Mr. Trump clearly has become more desperate to protect himself and those close to him," Brennan wrote, calling the clearance revocation "an attempt to scare into silence others who might dare to challenge him."
Hayden made a similar suggestion in an interview with CNN.
"The White House just messaged the entire American intelligence community," Hayden said. "If you stand up and say things that upset the president or with which he disagrees, he will punish you. And that is a horrible message to be sending to folks who are there to tell you objective truth."
The decision to revoke Brennan's security clearance drew a mixed reaction from Trump's fellow Republicans.
Sen. Bob Corker, R-Tenn., who chairs the Foreign Relations Committee, said he was bothered by the president's move.
"It feels very much like a banana republic kind of thing," Corker said.
Other lawmakers were less sympathetic towards Brennan.
Sen. John Kennedy, R-La., argued that the former CIA director's own rhetoric in criticizing Trump had cheapened the status of intelligence agencies.
"He's acted like a political hack, and not a national security professional," Kennedy said.
Brennan has been sharply critical of Trump, calling his comments after meeting with Russian President Vladimir Putin last month, "nothing short of treasonous." After Trump's attack this week on former White House aide Omarosa Manigault Newman, Brennan tweeted that the president failed "to live up to minimum standards of decency, civility, and probity."
Sen. Dianne Feinstein, D-Calif., the former chair of the Senate Intelligence Committee, who sparred with Brennan when he led the CIA, said Trump's decision, "harms our national security and once again shows how petty and thin-skinned President Trump truly is."
The decision to revoke Brennan's security clearance has evidently been in the works for weeks. The original statement released by the White House on Wednesday included a date of July 26, although aides said that was an error. The White House later issued a revised statement with that date removed.
NPR producer Barbara Sprunt contributed reporting to this story.
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