First, moderate conservatives could swing from Jeb Bush to Rubio. This is a pretty obvious scenario: Bush is (very) arguably the frontrunner overall, his entry into the race was thought by a lot of people to preclude a Rubio run, and he and Rubio have enough in common (both Floridians, both looked upon favorably by the party’s machers, both aiming for a similar mobility-oriented pitch on economics) that it’s easy to imagine that their fates are closely linked. Right now the two aren’t all that far apart in the national polls — Bush is “leading” the field with around 16 percent in the RealClearPolitics average, while Rubio is around 7 percent — and there’s no reason to think that Bush has any kind of hammerlock on moderate-conservative support. That support, historically, tends to take cues from the party apparatus, from mainstream as well as conservative media coverage, and from perceived electability. So the more Jeb struggles to establish any kind of clear lead or to demonstrate that his organizational prowess cashes out in votes, the more opportunity there is for Rubio to woo the media with his time-for-a-change narrative, to siphon off support in the invisible primary and to persuade potential Jeb supporters that he’s actually the better bet … with the endgame in this scenario probably being a New Hampshire win that catapults him into the pole position for Florida and beyond.

Alternatively, Rubio could gain ground relative to Jeb by siphoning support from some of the more conservative candidates in the race. There are various ways this might happen, but the most likely path would involve some movement of social conservatives, evangelical and Catholic and even Mormon (cue the Romney endorsement!), away from candidates like Cruz and Mike Huckabee and Ben Carson and toward the Florida senator. I’m not imagining Rubio peeling away the most conservative of these voters (the ones who really want Ted Cruz’s dad to run for president, for instance), but he has both the record and the rhetoric to win over some of them — younger evangelicals perhaps especially — and right now he seems more comfortable and fluid on issues related to faith, social issues, and religious liberty than either Scott Walker or a Rand Paul. Every campaign season there’s talk about how the religious right is going to unite around a single candidate and finally show the establishment what’s what, and every campaign season that doesn’t come to pass. But for religious conservatives who do want to vote strategically, Rubio might end up seeming like a better bet than Walker (who I suspect is going to be strongest among more secular conservatives) and the various unelectable others, and a savvy Rubio campaign might be able to take advantage of that potential appeal to run more strongly than anyone expects in Iowa (where 25 percent could win the caucuses again), and use that showing as his springboard rather than pushing all the campaign’s chips in on New Hampshire.

Or finally, Rubio could simply prove Cohn’s (again, very plausible) thesis wrong, and steadily gain support wherever he currently has solid favorable ratings — that is, more or less across the board. Instead of becoming the choice of moderates or the choice of (some) evangelicals, in other words, he would gradually become the choice of both groups and others as well … thanks to some combination of strong interviews and debate performances, stumbles by other candidates, and just the gradual solidifying of impressions as Republican voters begin to actually pay attention to the campaign. As I’ve argued before, Rubio more than most candidates fits the way many Republicans want to think about their party and ideology and cause; as Michael Brendan Dougherty put it earlier this week, supporting Rubio would just plain “feel good for Republicans,” because it could feel (as rooting for Obama has felt for Democrats) “like rooting for the universality of your principles, and for the future of your nation.” And it’s entirely possible that the desire (conscious or unconscious, but very small-d democratic either way) to experience that feeling, joined to a sense that Rubio really is more electable than his rivals, will eventually prove more powerful than faction, and a kind of party-wide tide will lift him to the nomination.