In a move that still might surprise the kind of people who think of a U.S. Senate seat as something you hang onto until you are crossing death’s door, Marco Rubio is set to announce a presidential candidacy in Miami tonight. In contrast to Rand Paul, he cannot run a dual campaign for president and Senate. And so despite poll numbers in the single digits everywhere, and a formidable home-state and National Establishment obstacle in his former mentor Jeb Bush, he’s taking the big leap.

The reason it might not be as risky as one might imagine is buried in an otherwise insufferably puffy Grunwald/Caputo piece at Politico

Rubio and his team do not like to talk about strategy, but in any case, the political calculus of giving up a Senate seat to seek the brass ring was not as painful as it sounds. Even if Rubio doesn’t win the nomination, he could well end up on the Republican ticket. Even if he ends up unemployed in 2017, he can run for governor in 2018 with a Republican-friendly mid-term electorate.

So why not get the requisite training-wheels run for the top spot out of the way? If his campaign never really takes off, it will be attributed to Bush’s strength rather than Rubio’s weakness. And for a dark horse, he’s very well positioned, with surprisingly strong approval/disapproval ratios in the early states–a sign the “base” is ready to accept his backtracking on immigration reform–and the possibility of replacing either Bush–whose own numbers remain questionable–or Scott Walker–one big gaffe or indictment away from Palookaville–in the first tier of candidates.

On top of all that, he’s the candidate Republican Establishment elites are almost certain to drool over if Jebbie blows up or fades. He’s the symbol of change in the GOP, without really making many concessions that strain conservative orthodoxy. A relatively young guy with a Latino background who is (it appears) the closest thing to a Reformicon champion (though again, what Reform Conservatives offer is more an add-on to conservative fiscal policy making it even more fiscally irresponsible than any sea change), and also a favorite of Neocons, is going to get massive positive media attention if and when he becomes more viable. Here’s how Halperin and Heilemann, who really are experts on this sort of thing, sum up Rubio’s media appeal:

Beloved by bookers and profile writers, earns a high percentage of stories that are favorable and on-message, and benefits from buzz generated by party elites wowed by his brand and delivery.

So at this point Rubio looks like a candidate who really can’t fail, at least until such time as he really is a top-tier candidate and distressing little things about his background (his relationship with scandal-ridden David Rivera, his bouts of nastiness) and his political appeal (there’s no real evidence he can win non-Cuban Latino voters over to the GOP) begin to get serious scrutiny. He really is the perfect second-tier candidate, though. If, for example, Bush and Walker get into some toxic competition that produced a political murder-suicide, it’s hard to imagine anyone benefiting more than Marco–unless it’s HRC.

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Ed Kilgore is a political columnist for New York and managing editor at the Democratic Strategist website. He was a contributing writer at the Washington Monthly from January 2012 until November 2015, and was the principal contributor to the Political Animal blog.