Via Mediaite, his strategy here is obvious. What I didn’t realize until Benjy Sarlin reminded me on Twitter was that Rubio’s not the first Republican to draw this comparison. Jeb Bush did it last week:

Mr. Bush, the former governor of Florida, told an audience in Iowa on Tuesday that voters ought to forget about tiny little things like “race and ethnicity and income.” And he attacked two people who he said were trying to scare and divide Americans – Mr. Trump and, incredibly, President Obama. “There are people that prey on people’s fears and angst as well,” Mr. Bush said. “Whether it’s Donald Trump or Barack Obama, their rhetoric of divisiveness is wrong.”

If you want a much, much fuller treatment of the analogy, see Victor Davis Hanson’s latest piece for NRO, “Obama and Trump: Two of a Kind.” For the past month, the CW among establishment Republicans was that Trumpmania would burn itself out quickly and had to be endured with patience until it did. (Rand Paul made that very point as recently as yesterday.) Now, with Trump in the mid-20s in national polling and getting saturation media coverage, people like Bush and Rubio are grasping for ways to pop the balloon so that it’ll deflate more quickly. You can call him a RINO, truthfully, but he’ll just call you one back. You can say he’s vulgar, but his fans like that about him. You can say that he wouldn’t stand a chance against Hillary, also truthfully, but no one cares about electability 16 months out and Trump can always retort that his polling is better than theirs right now.

The quickest way, in theory, to breed contempt for Trump among his admirers is to compare him to the most contemptible figure in the GOP’s political cosmology. He’s another Obama. It won’t work — their styles are too different, even if the sizes of their egos aren’t, and Trump’s birtherism established him squarely as an Obama antagonist — but you can see why Bush and Rubio might think it’s worth a shot. The odd thing about what Rubio says here isn’t the analogy itself but how superficial it is. The key similarity between Obama and a guy who’s supported all sorts of left-wing policies in the past, and who told CNN in 2004 that he probably identifies more as a Democrat, is that they’re both … not classy? C’mon. If you’re not going to hit him on policy, at least hit him on the fact that he and O are, in different ways, the consummate “celebrity” candidates. As one GOP strategist said to the Hill, “He’s the Kardashian of the Republican primary.”

What makes the “no class” attack especially weak is that, per today’s new Morning Consult poll, Trump has paid no price among voters for his classless moment over the weekend goofing on McCain. Trump fans don’t care about that. Why would they? He put the boots to a RINO. That’s what matters.

A new Morning Consult poll finds Trump leading the Republican field with 22 percent of the vote, well ahead of former Florida Gov. Jeb Bush, who clocks in with 15 percent, and Wisconsin Gov. Scott Walker, in third place with 12 percent… There is no evidence that Trump’s numbers have slumped after comments he made questioning Sen. John McCain’s (R-Ariz.) war record. Though most of the rest of the Republican field — and even the Republican National Committee — loudly criticized Trump after he made the comments on Saturday morning at an event in Iowa, voters interviewed afterward weren’t any less likely to say they support him. In fact, Trump has gained ground since a Morning Consult poll earlier this month, when he trailed Bush by a 19 percent to 17 percent margin. This week Trump is the second choice of 12 percent of voters, behind Bush’s 18 percent.

Criticizing Trump for his lack of decorum is like criticizing Bernie Sanders for being radically left-wing. It’s why their fans love them. It’s evidence that they haven’t been coopted by D.C.’s political culture. Really odd that Rubio thinks this would cost him votes, even if it’s dressed up in an Obama analogy.