When John Brennan assured the country that the CIA hadn’t improperly monitored the Senate team that compiled a report on Bush-era torture, he fed us false information. That much is clear from Thursday’s news that "the C.I.A. secretly monitored a congressional committee charged with supervising its activities." Either the CIA director was lying, or he was unaware of grave transgressions that were perpetrated at the agency where he is supposed to be in charge. Hence the calls for his resignation or firing from Sen. Mark Udall, Trevor Timm, Dan Froomkin, and Andrew Sullivan, plus a New York Times editorial airing his ouster as a possibility. President Obama could surprise us by axing his former counterterrorism advisor, explaining that under Brennan’s management, employees for whom he’s responsible broke laws and undermined the separation of powers core to our democracy. As Obama mulls what to do, he may well make a good faith effort to act in the national interest. But it’s impossible to believe that he won’t be aware of the following: that no U.S. official knows more than Brennan about Obama’s many drone killings. Some of the killings were solidly grounded in international law. Others may have violated the Fifth Amendment, international law, or the laws of war. In the past, Brennan has been willing to lie about those drone strikes to hide ugly realities. For example, Brennan stated in the summer of 2011 that there had been zero collateral deaths from covert U.S. drone strikes in the previous year, an absurd claim that has been decisively debunked. What if he grew more forthright, whether in public statements or by anonymously leaking information? Recall how intimately Obama involved himself in many killings: President Obama, overseeing the regular Tuesday counterterrorism meeting of two dozen security officials in the White House Situation Room, took a moment to study the faces….Mr. Obama has placed himself at the helm of a top secret “nominations” process to designate terrorists for kill or capture, of which the capture part has become largely theoretical. And how central a role Brennan played: Beside the president at every step is his counterterrorism adviser, John O. Brennan, who is variously compared by colleagues to a dogged police detective, tracking terrorists from his cavelike office in the White House basement, or a priest whose blessing has become indispensable to Mr. Obama… Finally, recall the chilling logic these two settled on: Mr. Obama embraced a disputed method for counting civilian casualties that did little to box him in. It in effect counts all military-age males in a strike zone as combatants, according to several administration officials, unless there is explicit intelligence posthumously proving them innocent. Even if Brennan told everything he knew, I’d still guess that the odds would be heavily against Obama ever finding himself on trial for civil rights violations or war crimes (though if I were Obama, I’d take proactive steps to lessen the odds further.) But I can imagine details that could cause Obama’s image to suffer, now and in the eyes of history; I can imagine him being subject to travel bans or indictments in absentia in certain countries; I can imagine aspects of his post-presidency suffering. We don’t now know, for example, what sort of legal authority Obama had the first time he ordered Anwar al-Awlaki to be killed, or why his 16-year-old son, an innocent American teenager searching abroad for his absentee father, ended up dead; or classified information about innocents killed in drone strikes. I am not suggesting that John Brennan is blackmailing Obama, or even that he would necessarily retaliate if fired. I am suggesting that if Obama is like most people in positions of power, he fires no subordinate without first asking himself, "Could this person damage me?" And if Obama is a normal person, rather than an unusually principled person, the answer then factors into his decision. Brennan isn’t unaware of this dynamic. And look what he said back in March, immediately after denying that the CIA spied on the Senate intelligence committee, when Andrea Mitchell asked if he’d resign his post if that turned out to be wrong: …if I did something wrong, I will go to the president, and I will explain to him exactly what I did, and what the findings were. And he is the one who can ask me to stay or to go. He’s a smart man. All this may be irrelevant to his continued tenure. Perhaps Obama has always believed and continues to believe that Brennan is doing a heckuva job. But just as secret torture acted as a cancer in the U.S. government, encompassing acts so barbaric and criminal that, even recently, the CIA spied on a Senate subcommittee investigating the subject, America’s semi-secret policy of semi-targeted killing rendered everyone involved complicit in activities sufficiently dubious that all desire their secrecy. Would you fire a guy who knows as much about your most morally fraught acts as Brennan knows about who Obama has killed in secret? Yeah, me neither. This isn’t the biggest cost of presidents who hide arguably illegal actions by declaring them state secrets. But it is certainly one of the costs. There’s inevitably a need to review the job performance of people party to these secrets. Lo, they typically keep their jobs. So George W. Bush left us a CIA staffed partly with people willing to torture. And Obama will likely leave us with a CIA that includes torturers, people willing to kill an American citizen in secret without due process, and people willing to spy on a Senate subcommittee as it does oversight. The Senate intelligence committee was established precisely to stop a trajectory this dangerous from playing out, but it is failing abjectly in its duties, as yesterday’s crimes spawn today’s efforts to spin or suppress those crimes. If the Senate doesn’t act now to rein in the CIA, what will it take?