Trump, Pompeo, and Mattis have spent weeks trying to persuade the Senate not to throw any grenades at U.S.-Saudi relations, whether by trying to end the logistical support that America’s providing to the Saudi effort in Yemen or by accusing Mohammed bin Salman of responsibility in the murder of Jamal Khashoggi.

The Senate did both today, voting 56-41 on Yemen and unanimously by voice vote on bin Salman and Khashoggi. The good news for hawks: This bill will remain only a bill for now, as the Republican House blocked an effort earlier this week to have a similar anti-Saudi resolution considered. The bad news: The House won’t be Republican-run for much longer. The interesting background question lurking here is who has ultimate authority to decide whether American forces participate in the Saudis’ Yemen war. Is it the president or Congress? The resolution that passed, authored by Bernie Sanders, wasn’t shy about addressing that issue.

Whereas section 5(c) of the War Powers Resolution (50 U.S.C. 1544(c)) states that “at any time that United States Armed Forces are engaged in hostilities outside the territory of the United States, its possessions and territories without a declaration of war or specific statutory authorization, such forces shall be removed by the President if the Congress so directs”;

Whereas section 8(c) of the War Powers Resolution (50 U.S.C. 1547(c)) defines the introduction of United States Armed Forces to include “the assignment of members of such armed forces to command, coordinate, participate in the movement of, or accompany the regular or irregular military forces of any foreign country or government when such military forces are engaged, or there exists an imminent threat that such forces will become engaged, in hostilities,” and activities that the United States is conducting in support of the Saudi-led coalition, including aerial refueling and targeting assistance, fall within this definition;…

Congress hereby directs the President to remove United States Armed Forces from hostilities in or affecting the Republic of Yemen, except United States Armed Forces engaged in operations directed at al Qaeda or associated forces, by not later than the date that is 30 days after the date of the adoption of this joint resolution (unless the President requests and Congress authorizes a later date), and unless and until a declaration of war or specific authorization for such use of United States Armed Forces has been enacted.

The War Powers Act was passed in 1973 as a reaction to Vietnam. Congress was tired of letting the president wage undeclared war without end so it clawed back a little — a little — power over military operations. Nixon vetoed the bill but the veto was overridden by supermajorities in both houses of Congress. You can read it here. In a nutshell, absent any congressional authorization, it imposes a time limit on how long the president can keep U.S. forces engaged in “hostilities.” Presidents since Nixon have tended not to pay much attention to it unless they’re undertaking a truly massive open-ended operation like the invasion of Iraq, where some symbolic buy-in by the people is required. Congress is usually fine with that arrangement since their chief goal nowadays is avoiding responsibility for the nation’s problems wherever possible. If there’s something the president wants to do abroad militarily and it’s not so huge an undertaking that Congress absolutely must weigh in, great. Go nuts. Let him take sole blame if something goes wrong.

Today’s vote is unusual inasmuch as the Yemen war is a classic small-scale operation (for us, not for Yemenis, lord knows) and yet here’s the Senate ordering Trump to bring the boys home. And they did it with bipartisan support, with seven Republicans voting yes on final passage: Collins, Daines, Flake, Moran, Paul, Young, and most notably Mike Lee, who co-sponsored the bill and made an extended argument against the war — and in support of the War Powers Act — on the Senate floor a few weeks ago. Read his speech if you missed it earlier. It surprised me at first to find Lee on this side of the issue, as his recent defense of Trump on Jeff Flake’s “protect Mueller” bill was fresh in my mind. (As was the fact that most righties seem to believe the War Powers Act is unconstitutional as an infringement on the commander-in-chief’s authority over the military.) But there’s no contradiction. Lee thinks Flake’s bill is unconstitutional because Article II makes clear that executive-branch officers answer ultimately to the president. Can’t go handing Trump’s power over Mueller to the judiciary. The Constitution is *not* perfectly clear about authority over war, though. The president directs the military but Congress is given the power to initiate hostilities by declaring war. Lee’s belief in that is what ultimately led to this unusual alliance with far-left Bernie Sanders.

It’d be fascinating if the Yemen standoff between Trump and the Senate led to a real battle over the War Powers Act. I just don’t see how it happens. Even if the Democratic House passes Sanders’s resolution next year, Trump will veto it. Then both houses will have to somehow produce two-thirds majorities to override the veto. *Maybe* Pelosi can do it, although I highly doubt it, but there seems no way to make it happen in a Republican-run Senate. Failing a veto override, members of Congress would presumably have to sue Trump to try to enforce the War Powers Act as it applies to Yemen. Would they even have standing? Who would sue? Pelosi?

Two clips for you here, one of Sanders this afternoon following the big vote and the other of Lindsey Graham. Graham voted no on the Sanders/Lee bill, as he doesn’t want to fight with Trump over the War Powers Act. Instead he and Bob Menendez are pushing a different resolution that would suspend arms sales to the Saudis instead of yanking U.S. support for their war effort. Graham thinks that bill will attract everyone who voted today plus some other Republicans, which is probably true. In that sense, he’s helping Trump out here by steering his colleagues towards a less draconian bill. But POTUS can’t be happy watching even an ostensible ally like Graham haggling with Democrats over just how much to tie the president’s hands on aiding the Kingdom. The tide is against him here.