For Donald Trump, it always comes back to winning — and greatness. So his response to Marco Rubio scoring some hits in last night’s debate was to immediately seize control of the news cycle by appearing with Chris Christie at an extraordinary news conference, at which Christie endorsed Trump and absolutely torched Rubio as a lightweight fop whose new “act” is to “be entertaining and smile a lot.”

Trump was equally merciless, hammering Rubio as a loser and a choker who doesn’t have what it takes to win in November, let alone what it takes to make America great again. In one particularly subtle moment, Trump even noted that during a backstage encounter, he’d seen Rubio’s sweat cause his makeup to run.

It’s easy to see this as another diverting moment, as another sign that the GOP is melting down, at least for the moment, as Republicans struggle to derail Trump. But I think this should not be seen as burlesque. The Donald is plainly serious about this President Trump stuff, and he now could actually win the nomination. The point about the Christie endorsement is not that it will help him in any concrete way in the remainder of the primaries — it’s hard to know whether it will or not — but rather that Trump found a way to stomp on Rubio’s big moment just when it looked as if Rubio had located a way to take Trump on.

Meanwhile, beyond the primaries, Democrats need to pay attention to what Christie said about the general election in explaining his endorsement:

“There is no doubt in my mind that the single most important thing for the Republican Party is to nominate the person who gives us the best chance to beat Hillary Clinton. I can guarantee you that the one person that Hillary and Bill Clinton do not want to see on that stage come next September is Donald Trump. They know how to run the standard political playbook against junior senators, and run them around the block. They do not know the playbook with Donald Trump, because he is rewriting the playbook. He’s rewriting the playbook of America politics, because he’s providing strong leadership that’s not dependent upon the status quo. The best person to beat Hillary Clinton in November on that stage last night is undoubtedly Donald Trump.”

There are some problems with this, of course. It’s far too dismissive of Rubio’s chances in a general election, I think. Rubio as the nominee would stand a legitimate chance of scrambling demographic expectations by cutting into Democratic voter groups such as Latinos and young voters. Rubio’s generational message seems like it could create a powerful contrast with Hillary Clinton in particular. Rubio has shown that he is capable of learning and adapting as a candidate. And it’s certainly possible, as many Republicans believe, that a Trump nomination could produce an epic disaster for the GOP, resulting in a massive rout among Latinos and women and unleashing a down-ticket bloodbath as well.

But Christie’s suggestion that Trump’s very unpredictability could render him a lot harder to beat in a general election than many expect is very much worth entertaining.

It turns out some Democrats agree with Christie’s general analysis. Alex Seitz-Wald and Benjy Sarlin report today that some Democrats are coming around to the view that anything could happen in a Trump-Clinton match-up. This conversation with left-leaning demographics expert Ruy Teixeira is noteworthy, as is what follows:

If his populist message boosts turnout and margins with working class white voters high enough in the Rust Belt and Upper Midwest, he could win even while alienating black and Latino voters. “You could see a situation where someone like Trump could carry Ohio, Iowa, Wisconsin, maybe Pennsylvania,” he said. “That starts to put a real dent in the Democratic coalition.”
While Trump’s offensive language is undoubtedly a huge liability in a general election, it’s also a dangerous weapon. He’s already accused Bill Clinton of being a sexual abuser, an attack no other candidate is likely to level at the former president and one that some observers think contributed to Hillary Clinton’s drop in polls in the beginning of the year.
The attack on Bill Clinton seemed to unsettle the former secretary of state’s campaign. After spending months blasting Trump without hesitation, Hillary Clinton suddenly had nothing to say about him….
People familiar with the Clinton campaign’s thinking say they’re confident she can beat Trump – but that the race would likely to be much uglier and potentially more damaging than against another nominee. People are “insane” if they think this will be a walkover, one pro-Clinton operative said.

Now, obviously some Republicans will see this as a head fake — as an effort to suggest that Democrats fear Trump, even if they don’t, to boost Trump’s chances in the GOP primaries. But some Democratic strategists, such as Simon Rosenberg, genuinely believe that Trump has tapped into something that could matter in a general election — a sense that our elites and our system are failing us, and even more crucially, that they no longer actually think the system can be made to work — and that Clinton is at risk of being seen as a conventional, defeatist, establishment politician, as part of the problem.

It’s been reported that Democrats are developing a strategy to take on Trump that revolves around using his business dealings to do a kind of Bain-Romney-redux play. I think that Rosenberg is right, and that such a strategy might not be good enough.

To reiterate, it’s perfectly plausible that Rubio would make a substantially stronger general election candidate than Trump. Rubio still has a real chance at beating Trump, too. But nonetheless, it’s a strange, unpredictable year, and nothing is going according to expectations. Rubio might lose, and Trump might actually be the nominee. As noted above, Trump could prove disastrous in a general election. But we can’t be certain of that. Whatever Chris Christie’s motivations in backing Trump, what he said today about the general election deserves to be taken seriously.

New Jersey Gov. Chris Christie endorsed Republican presidential candidate Donald Trump for president on Friday. Here's what the two have said about each other. (Victoria Walker/The Washington Post)