There are two ways to look at Thursday’s Senate vote to block President Trump’s attempt to build a wall on the southern border without congressional approval by declaration of a national emergency.

On the one hand, Congress laudably stood up for its constitutional prerogatives as the country’s lawmaking body, rebuking the president for his executive power-grab and forcing him to issue his first veto. On the other hand, Senate Republicans—including some who have talked a lot about opposing Trump’s erratic actions—overwhelmingly rolled over and voted to let Trump’s emergency go through.

In a funny way, even though the vote was largely symbolic, it turned out to be revealing.

In the end, only 12 GOP senators broke ranks and voted to rebuke the president: moderates Susan Collins and Lisa Murkowski; tea-party types Mike Lee, Marco Rubio, and Rand Paul; and traditional conservatives Mitt Romney, Lamar Alexander, Roy Blunt, Rob Portman, Pat Toomey, Roger Wicker, and Jerry Moran.

The dividing line, it turns out, was first and foremost the election cycle: Collins was the only Republican up for reelection in 2020 to defy the president. Two other 2020 incumbents—who were widely expected to break with Trump—fell in line at the last minute. One, Thom Tillis of North Carolina, was particularly odd: his eleventh-hour cave came just weeks after he wrote an op-ed proclaiming his opposition to the national emergency in the grandest terms.

“Conservatives rightfully cried foul when President Barack Obama used executive action to completely bypass Congress and unilaterally provide deferred action to undocumented adults who had knowingly violated the nation’s immigration laws,” Tillis wrote. “Some prominent Republicans went so far as to proclaim that Obama was acting more like an ‘emperor’ or ‘king’ than a president. There is no intellectual honesty in now turning around and arguing that there’s an imaginary asterisk attached to executive overreach—that it’s acceptable for my party but not thy party.”

Tillis’ piece was literally headlined “I support Trump’s vision on border security. But I would vote against the emergency.”

Then a couple days ago, rumors bubbled up that Tillis might face a primary challenger if he continued to defy the president. Presto: He voted with the emperor king after all.

The other notable vote was Nebraska senator Ben Sasse, who occupies something of a sour spot: Trump’s supporters dislike him because of his frequent criticisms of the president. But people to the left of center scorn him for supporting Trump’s agenda even as he talks about the damage Trump is doing to our constitutional and democratic norms. Thursday’s vote seems likely to add to his troubles.

Sasse kept his head down on the emergency declaration until the vote and then issued a vaguely ridiculous statement arguing that, “Today’s resolution doesn’t fix anything because the root problem here can’t be fixed with bare-knuckled politics but rather with a deliberate debate about the powers that Congress has been giving away and that the Executive has therefore claimed.”

Saying nothing until the moment you fall meekly in line while protesting that the debate about Congress giving away its power hasn’t happened yet is . . . well, it’s unclear what, exactly, that is.

The capitulations from Tillis and Sasse are only disappointing because we had reason to expect better. Folks like Ted Cruz, on the other hand, don’t even really disappoint any more: the cocky Founders-quoting firebrand of yesteryear traded in his tight-lipped, finger-wagging Constitutionaler-Than-Thou routine to cheerlead for Trump ages ago.

And that’s to say nothing of the shambolic mass of the relatively faceless rank-and-filers who thudded into line more or less in unison.

There’s still a chance the damage might not be permanent. Republicans know how bad this makes them look; they know the ridiculously vulnerable place they’ve put themselves in. In the weeks to come, you can bet they’ll do whatever they can to shut the door behind Trump—to cut off presidential access to emergency powers to ensure that future Democratic presidents can’t treat this as a grievous precedent. (While leaving this emergency declaration intact, of course—what’s done is done!) In that sense, their hope seems to be that they can make this a one-time nuclear option that only they got to take advantage of and will be locked away forever beyond the reach of Democrats.

Good luck with that.

Funnily enough, Trump has signaled that he might support such legislation in the future—although it’s even harder to take him at his word here than usual, as he cut such legislation off at the knees only yesterday.

Meanwhile, Democrats are in no rush to let Republicans off the hook—Nancy Pelosi has already indicated she won’t even look at national emergency reform legislation that grandfathers in Trump running wild at the southern border. And why should she? They’re eyeing a re-aligning election in which the Democratic party wants to be able to enact its wildest dreams, no matter what the legislative process yields.

Whatever happens, one thing is clear: Thursday’s vote is a stain on the GOP, the undoing of years of promises to America that they were the party of the rule of law, of the Constitution, of the separation of powers, and limited government.

That may have been true once. But those days are clearly over.