Director of the Central Intelligence Agency
"His efforts to protect himself at all costs could come at the cost of this country's security," the former CIA director said.
Trump's tweet follows a lengthy interview in which Brennan harshly criticized Trump.
"These are frightening times," former CIA director tells Rachel Maddow.
The former CIA director, whose security clearance was revoked by Trump a day earlier, hit back in an op-ed in The New York Times.
Democrats had the power to block her nomination, but they couldn't stick together.
The aide reportedly tossed out the cruel remark in response to the senator's opposition to the CIA director nominee.
Cheney's comments come as lawmakers have scrutinized CIA director nominee Gina Haspel for her role in overseeing the controversial program.
The Democratic senator "would rather give ... terrorists hugs and safe spaces than take adequate action to protect America," state Sen. Leah Vukmir (Wis.) said.
Confirming Mike Pompeo as America's chief diplomat will send a troubling message to the rest of the world.