But … but that’ll help Trump. Can’t Obama see that? If a man as distrusted by Republicans as O starts name-checking Trump as a special threat, undecided GOPers will rally around him. That could be the difference in a close race with Cruz and/or Rubio. Why would Obama do something that’s likely to increase Trump’s chances at the nom—-

Oh. Ohhh.

According to people in the White House, Obama doesn’t talk about Trump much. When he does, it’s with a combination of amusement and disgust at the rhetoric, occasionally mentioning his amazement at GOP leaders’ inability to understand Trump’s supporters and the long-term damage the president thinks Trump is doing to the party with the groups of voters who will decide future elections…

“In the long sweep of history, this chapter is all pretty simple: The country actually switched from one dominant culture that was in charge for 240 years to one that’s multicultural,” said one Obama campaign veteran. “And that wasn’t going to go easy. But now we’re in the middle of it, so it seems chaotic and complicated.”…

Going into next year, Obama will be speaking out against Trump, as he did indirectly in several pro-immigration speeches earlier this month and by name in an interview with NPR last week, when he argued that the Republican front-runner is exploiting the fears of “particularly blue-collar men [who] have had a lot of trouble in this new economy.” And pushing back against Trump will be a central theme of Obama’s international engagement.

If this sounds familiar, it’s because Democrats used the same strategy to brilliant effect in the 2012 Senate race in Missouri. The GOP primary was jammed up with three candidates; Claire McCaskill, the Democratic incumbent, wanted to do something to help Todd Akin win, believing (correctly) that Akin would be the easiest of the three to beat in a general election. The solution: Start attacking Akin before the Republican primary, knowing that a big-name Democrat’s official seal of disapproval would be a strong lure to Republican voters to consider Akin. Some of that is pure tribalism at work — Democrats are bad, therefore things they dislike must be good — and some of it is “they’ll tell you who they fear” reasoning at work. The problem is, sometimes they’re not telling you who they fear when they attack. Sometimes they’re telling you who they don’t fear and hoping you’ll fall for it. In McCaskill’s own words:

Using the guidance of my campaign staff and consultants, we came up with the idea for a “dog whistle” ad, a message that was pitched in such a way that it would be heard only by a certain group of people. I told my team we needed to put Akin’s uber-conservative bona fides in an ad—and then, using reverse psychology, tell voters not to vote for him. And we needed to run the hell out of that ad…

This presentation made it look as though I was trying to disqualify him, though, as we know, when you call someone “too conservative” in a Republican primary, that’s giving him or her a badge of honor. At the end of the ad, my voice was heard saying, “I’m Claire McCaskill, and I approve this message.”

It started to work. Our telephones were ringing off the hook with people saying, “Just because she’s telling me not to vote for him, I’m voting for him. That’s the best ad for Akin I’ve ever seen!”

McCaskill knocking Akin will have a fraction of the reverse-psychology appeal that Obama knocking Trump could have, and of course Obama knows that. If I were him, I’d maximize the impact by holding off on hitting Trump until the last week of January, when Iowans and New Hampshirites start making up their minds, and I’d specifically accuse Trump (a la McCaskill and Akin) of being “too conservative” for America. The more Obama can build up Trump’s ideological bona fides, the more undecided Republicans will consider him a suitable alternative to Cruz and Rubio. Obama will take some flak for that even from his own side on the theory that if, as some critics argue, Trump has been flirting with fascism then it’s irresponsible to promote him even if you think he’s a sure loser in the general election. But the White House counter to that will be simple: He’s a sure loser in the general election. His favorable rating among the wider electorate averages net -23. Even some Republicans will refuse to back him if he’s the nominee. Hillary can’t lose! Which is … probably true, but there’s a lot of risk hidden in that “probably,” as even some liberals admit. She’ll be better organized than Trump will, she’ll raise more money than Trump will, but she’s a black hole of charisma and he’s got enough of it to power a city. If he spends most of the campaign talking about wages and jobs, he’ll contend. Especially in a country where each major party nominee realistically is looking at a floor of 45 percent in a national election.

Remember the last time Obama laid into Trump publicly? Last time it was personal; this time it’s business.