As a matter of constitutional decency, the president should have submitted the deal to Congress first. And submitted it as a treaty. Which it obviously is. No international agreement in a generation matches this one in strategic significance and geopolitical gravity.

Obama did not submit it as a treaty because he knew he could never get the constitutionally required votes for ratification. He’s not close to getting two-thirds of the Senate. He’s not close to getting a simple majority. No wonder: In the latest Pew Research Center poll, the American people oppose the deal by a staggering 28-point margin.

To get around the Constitution, Obama negotiated a swindle that requires him to garner a mere one-third of one house of Congress. Indeed, on Thursday, with just 42 Senate supporters — remember, a treaty requires 67 — the Democrats filibustered and prevented, at least for now, the Senate from voting on the deal at all.

But Obama two months ago enshrined the deal as international law at the U.N. Why should we care about the congressional vote? In order to highlight the illegitimacy of Obama’s constitutional runaround and thus make it easier for a future president to overturn the deal, especially if Iran is found to be cheating.