Ever since the White House secured its framework agreement with Iran to prevent the state from developing atomic weapons, the administration has been focused on shoring up American domestic support for the prospective nuclear deal. Facing the prospect of a veto-proof majority in the Senate for a bill that would reassert CongressÂ’s authority to ratify foreign agreement, the White House appears to have backed off its earlier opposition to allowing congressional lawmakers the ability to scrutinize and approve of the arrangement with Iran. But extending to the dealÂ’s critics on Capitol Hill the power to modify its terms could...