Corker’s the guy who brokered a “compromise” in the Senate on Obama’s nuclear deal with Iran. Instead of insisting that the final agreement be regarded as a treaty, requiring the support of two-thirds of the chamber for ratification, Corker proposed letting naysayers try to block the treaty with a resolution of disapproval instead. The resolution could be filibustered by Democrats before it’s enacted, or it could be enacted and then vetoed by Obama. The only way to guarantee that the resolution will become law is to have a veto-proof majority — two-thirds of the Senate — willing to vote against it, a near-impossibility when the GOP controls only 54 seats. Corker, in other words, reversed the constitutional presumption that treaties are deemed blocked unless they receive supermajority support so that a final agreement with Iran will be deemed passed unless it receives supermajority opposition. He farted away all of hawks’ leverage, signaling to Obama that he could make as bad of a deal as he wants and all he’ll need to ensure that it gets through the Senate is 34 Democratic votes. Even an O weakened by the Democratic revolt over TAA can still swing 34 votes.

So Corker made it possible for Obama to concede as much as he likes without fear of legislative consequences. And now he’s pretend-surprised to find O in concession mode with Iran. I can sort of tolerate being sold out by congressional Republicans, if only because it’s become so routine. What I can’t understand is why they insist on insulting our intelligence in going about it.

If Corker suspected Obama’s team might agree to a deal at any cost in order to secure a “legacy” for their boss, why would he forfeit the Senate’s leverage over the deal? The point of the Treaty Clause is to ensure that the terms of an agreement with a foreign power are so favorable to the U.S. that a supermajority of the Senate will be willing to vote for it. Corker reversed that logic so that the Iran deal takes effect if it makes Obama and a few dozen of his most loyal Democratic cronies happy. And his letter doesn’t remotely capture all the damage that’s apt to result from this: Corker’s focused on how lousy the terms of nuclear inspections might be but journalists who follow the Middle East are increasingly worried about what lifting sanctions will do to the politics of the region. One silver lining in the dark ISIS cloud is that the wars in Syria and Iraq are bleeding Assad, Hezbollah, and Iran dry. If the jihadis manage to cut off Syria from Lebanon, writes Tony Badran, it could mean the end of both of Iran’s key proxies, leaving Tehran with far less reach around the region. The only thing that might prevent that now is … if the U.S. lifts sanctions on Iran pursuant to a nuclear deal, giving the regime an economic shot in the arm. It’d be nice if the Senate had some say over whether America should commit that particular blunder at a moment as fraught as this.

Exit question: What’s Corker’s game with this letter? Who’s he trying to persuade by suddenly acting shocked, shocked to find Obama behaving irresponsibly in the absence of congressional oversight? I assume this is an elaborate form of “failure theater,” in which the GOP willingly capitulates to O while trying to make it look to their base like they put up a tough fight before being outmaneuvered. The more indignant Corker appears to be that Obama’s screwing up negotiations, the harder it’ll be convince Republicans who are barely paying attention to this that the party made this sellout possible by not insisting that the Iran deal be regarded as a treaty. If that’s not what Corker’s doing here then I can only assume he really is genuinely surprised to find that this deal may be worse than he feared, in which case he’s too much of a schmuck to be in the Senate. Which, given the usual standards of schmuckery there, is really saying something.