367 Congressmen, representing a veto-proof majority of the House of Representatives, have signed on to an open letter in which they warn President Obama against reaching any Iran deal without first giving Congress the power to approve of block the pact.

The letter reflects efforts from Congressional leaders, lobbied heavily by Israel, to try to prevent President Obama from reaching a nuclear deal of any sort with Iran.

Though it drew comparisons to the recent letter from Senate Republicans warning against the deal, that letter was addressed to Iran itself, and warned the Congress would disavow the deal after the fact. This letter, instead, is urging the president to give Congress oversight on the talks, albeit with an eye on the same end of killing the negotiations.

It is less of a legal landmine than the Senate letter, but potentially a more important letter overall, as it represents a veto-proof majority, and if all those signatories actually back legislation to that effect, the Obama Administration will struggle to do much about it.