Republican presidential candidate Donald Trump said "the loser of the night was Marco Rubio" during his celebratory speech on Super Tuesday. "At least you can say that Ted has won something," the frontrunner said. (Video: Reuters/Photo: Jabin Botsford)

THE MORNING PLUM:

Donald Trump did not totally dominate last night, but the Super Tuesday results may have set in motion a process that is effectively closing the window on any chances to stop him. Trump only won around 35 percent of the overall Republican vote, and his delegate lead is not as formidable as it could have been.

Still, in winning seven states, Trump confirmed that he can win all over the country and can make inroads among many different subgroups of Republican voters. The results — Ted Cruz won three states; Marco Rubio took one; and Kasich outperformed Rubio here and there — will also likely encourage all three to stay in the race until March 15th, possibly making it harder still to slow Trump’s march to the nomination on that crucial date.

So now what?

Some Republicans are vowing to continue the resistance, with a group of major, deep-pocketed donors announcing new plans for a massive ad campaign to stop Trump. Others are talking about backing a third party run. Still others are suggesting that, even if all three non-Trump candidates remain in the race, that could actually facilitate efforts to force a contested convention, because it might deny Trump an outright majority of delegates.

But here and there, you can see signs of acceptance and acquiescence, and these signs give us a hint as to how Republicans might justify to themselves the eventuality of getting behind Trump as their nominee. They break down into three categories.

1) Trump is not quite as awful as Hillary is. Here’s former New Hampshire Governor and Senator Judd Gregg:

 And if Trump won? Gregg would support him. “What’s the option, Hillary Clinton?” asked Gregg. “I’d rather have somebody a little light on substance than somebody who put our national security at risk.”

“A little light on substance” is an interesting euphemism, but look for more of this sort of thing. We might see a quiet migration from “Trump’s wretched xenophobia, bigotry and tendency to regard the Constitution as a sh*t-stained piece of toilet paper have no place in the GOP,” to “Trump’s deeper instincts are concerning, to be sure, but they are not nearly as dangerous as Hillary’s are, and he can probably be set right with a little schooling.”

2) Trump doesn’t have deeply held principles, so he’ll probably work with us. Politico reports that Paul Ryan and Mitch McConnell have developed “rules of engagement” with Trump, in which they will criticize him when he acts like a hateful, dangerous lunatic, while leaving little doubt that they will back him if he’s the nominee. Note this:

Some in the Capitol believe there’s a slight upside in Trump’s candidacy. They don’t believe he has deeply held beliefs, and therefore can be persuaded to adopt the House GOP’s forthcoming agenda. Others say a Trump-fueled increase in voter turnout could help the party in some races.

In other words, Trump can’t possibly believe all the crazy, reckless nonsense he’s spewing, because it’s so crazy and reckless. That seems like a pretty big gamble.

3) Trump is already showing signs of growing. As Jonathan Cohn points out, at Trump’s victory presser last night, he seemed to pivot towards a slightly softer tone and a more general-election-friendly message. This led Newt Gingrich to remark:

This is something Democrats should take seriously as a real possibility, for purposes of the general election battle. But in the near term, it may be a sign that Republicans are prepared to decide that Trump is showing a capacity to grow.

Trump’s continued march to the nomination effectively stamps out most of the embers of hope among Republicans that he can be stopped by conventional means, i.e., by the voters. As Tim Alberta writes: “They had hoped Tuesday would bring evidence that Trump’s appeal was abating, and that the electorate was ready to rally around a single challenger to defeat him. They were disappointed on both fronts.”

As results showed Donald Trump leading in at least six states on Super Tuesday, Sens. Ted Cruz (R-Tex.) and Marco Rubio (R-Fla.) argued that nominating him would be bad for the Republican party. Here are key moments from their speeches following the March 1 races. (Sarah Parnass/The Washington Post)

To be clear, it’s very possible that a sizable chunk of Republicans will remain committed to fighting Trump all the way to the convention, and perhaps even beyond. Perhaps Rubio is right to predict that most Republicans will decide that getting behind Trump is simply not an option, because so doing would reduce the GOP and conservatism to smoking wreckage. It’s also possible that he will be denied a majority of delegates and see the nomination taken from him at a contested convention. But if you do see more Republicans move into the Trump-acceptance camp, the above rationales will likely be employed to justify it.

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 * CLINTON DOMINATES, BUT SANDERS WILL HANG IN THERE: Hillary Clinton won in seven states last night, piling up a delegate lead that will likely be very hard for Sanders to overcome. But the Post reports that Sanders plans to push on:

Sanders remains a potent force who can pull Clinton to the left and force her to spend money and other political resources…Sanders’s campaign boasted Tuesday that he had raised more money in February, almost all of it in small amounts, than Clinton. The campaign also announced late Tuesday that it would host a “path forward” breakfast for the media Wednesday…Sanders’s team has mapped out a busy schedule in coming days, with events planned in Maine, Michigan, Nebraska, Kansas, Missouri, Illinois and Ohio.

As I’ve argued, there is every incentive for Sanders to stay in, to try to build a national constituency among young voters and exert leverage over the convention and the party’s agenda in the general election. He’s got the money to do it, too.

* A VERY BAD NIGHT FOR MARCO RUBIO: Nate Cohn argues that Trump’s showing was not all that dominant, revealing that he might still be stopped in various scenarios, while summing up Rubio’s night this way:

The night could not have gone much worse for Marco Rubio….He failed to win Virginia, his best prospect of a primary victory. He has won in Minnesota, but it will be hard for him to claim any great strength with one caucus win in what was already poised to be his best state….with Mr. Cruz and Mr. Kasich all beating or exceeding expectations, and Mr. Rubio failing to counter with strength of his own, it is hard to imagine either Mr. Kasich or Mr. Cruz leaving the race soon.

It’s worth adding that all this happened after Rubio got down into the gutter with Trump, while Cruz and Kasich mostly refrained from doing that.

* MITT ROMNEY TO SAVE THE GOP? CNN reports on private discussions underway among top Republican strategists and insiders about the various paths forward, now that Trump may well be the GOP nominee:

Disaffected Republicans are discussing everything from skipping the Republican National Convention in July to running a conservative candidate as an independent or third-party candidate — with the ultimate goal of denying Trump the presidency. One of the names frequently mentioned in this hypothetical is Mitt Romney, the 2012 GOP presidential nominee, even though he has shown no desire to run another campaign but has shown a zest for attacking Trump.

This would give Republicans a way of asserting that they will not make peace with Trump, even at the cost of the White House, which would probably happen even if they did get behind him.

* TED CRUZ FACES TOUGH ROAD AHEAD: The New York Times write-up asserts that Cruz’s success yesterday has given strength to his assertion that he should stay in the race. But:

Still, Mr. Cruz also showed the limits of his political reach: He did not come close to Mr. Trump in much of the South, he failed to resonate in more moderate Massachusetts and Virginia, and the lineup of states that vote later in March may be less hospitable to his brand of rigidly ideological politics.

Of course, Cruz has no real incentive not to stay in — if the GOP loses the White House after declining to nominate the only True Conservative in the race, that would only prove that he was right all along.

* THE MAP FAVORS DONALD TRUMP LATER: It’s often observed that Trump’s momentum might be slowed in the big, winner-take-all states that vote on March 15th. But Tim Alberta delivers the bad news to Republicans:

After that, April sees the race move to Trump’s wheelhouse: the northeast. Tuesday’s result in Massachusetts previewed how tough Trump will be in his own backyard: He won 49 percent of the vote, beating Kasich, the next-closest finisher, by more than 30 points. It may still be possible to prevent Trump from securing 1,237 delegates. But it’s now impossible to envision anyone else arriving in Cleveland as the Republican nominee.

That would mean there are only two options: Trump wins the nomination outright; or a contested convention.

 * REPUBLICANS EYE A CONTESTED CONVENTION: MSNBC’s Benjy Sarlin takes stock of the results and writes:

At this point it’s looking like it will take a contested convention, in which no candidate has a majority of delegates, to oust Trump. With that scenario in mind, anti-Trump Republicans seemed split on Tuesday between whether it would be better to try and consolidate behind one candidate or encourage candidates to remain in the race to have a better chance of denying Trump an outright majority.

So, not only are Republicans divided over whether to try to bring about a contested convention; they’re divided over how they might even pull that off.

 * AND HOW LONG WILL REPUBLICANS STICK BY RUBIO? Senator Lindsey Graham says what must not be said:

“You know Ted Cruz is not my favorite, by any means,” Graham, who dropped his own bid for the White House in December, said in an interview with CBS. “But we may be in a position where we have to rally around Ted Cruz as the only way to stop Donald Trump, and I’m not so sure that would work.”

In other words, maybe it’s time to admit that Rubio might not be the guy to take down Trump in a head-to-head match-up, after all. Will more Republicans come around to this position?