Ross Douthat asks why Rubio isn’t winning:

Nobody’s sure why. Rubio has various weaknesses, but he’s well liked by Republican voters, he polls very well against Hillary Clinton, and nothing scandalous has emerged to derail him. Yet here we are just days from Iowa, and prominent Republicans are variously frustrated and confused, resigning themselves to Trump-versus-Cruz or attempting complicated bank shots to take one or both of them out … instead of doing what many people expected and simply rallying to Rubio.

Douthat offers some possible explanations, and there is some truth to each of them, but they leave out something. It’s true that his immigration record and opportunism have hurt him, and he is pushing a reheated Bush-era agenda ill-suited to the present Republican mood. While it is often taken for granted that Rubio is the one that party leaders and donors should get behind, he has scarcely any qualifications to be president. He has nothing like the executive experience that the other “establishment” candidates have in spades. (If you judged Rubio against Kasich or Bush just on their resumes, he is hardly the obvious “establishment” choice.) Rubio also ran away from the only major piece of legislation that he worked on in his one term in the Senate. That does not exactly scream leadership material to the people that are “supposed” to rally behind him. The fact that Rubio continues to struggle despite overwhelmingly favorable coverage in the press has to make potential supporters worry about just how competitive he would be in a general election in which he would have no such advantage.

Many people are impressed by Rubio because he delivers speeches well and performs capably in debates. He is smooth and fluent when speaking about policy (even if the things he’s saying about it happen to be dangerous or nonsensical). That may make him seem “manifestly superior” to his “establishment” rivals, since no one would confuse either Kasich or Bush for a great debater, but it’s not enough to win and keep broad support from skeptical voters. The sort of voters Rubio needs most would seem to be the ones most likely to put great stock in experience, and in terms of both executive experience and experience at the national level Rubio has virtually none. (He doesn’t really have much foreign policy experience, either, but that’s another story.) His boosters want to see him as “the Republican Obama” (young, charismatic, ethnic, etc.), but a lot of the voters he needs to win over are wary of Rubio precisely because of his relative inexperience. He is too green on the national stage while still being a lifelong politician, which is not a great combination. On the one hand, he is stuck with the baggage of being seen as a preferred candidate of party elites, but he doesn’t meet the criteria that “establishment” candidates’ voters have for picking a nominee.

The simplest explanation is that Rubio isn’t winning because he hasn’t put in the time or effort into campaigning in the early states that other candidates have, and he also hasn’t built up much of a campaign organization. (Contrast this with Obama’s 2008 campaign, which had a very strong ground game.) Rubio banked on building up support primarily through debate performances and television ads. One of Rubio’s latest ads inadvertently acknowledges Rubio’s weirdly lazy campaign for president by showing voters watching Rubio on television. That is probably how most people in Iowa and New Hampshire have encountered Rubio, and it helps explain why there isn’t much enthusiasm for him in either place. Rubio gives the impression of someone who doesn’t want to bother with the legwork of being a candidate, and especially in states where voters expect a lot more personal attention that just doesn’t cut it.

Another factor that gets overlooked in all this is Rubio’s speaking style, which often leaves the impression of an overly-rehearsed and overeager show-off. Leonid Bershidsky watched Rubio campaigning in Iowa and described what he saw:

Rubio is earnest, humorless, prone to long stories about his poor childhood in an immigrant neighborhood and his gratitude toward the country that gave his family a home and him a chance at a bright political future.

According to Bershidsky, the crowd responded politely to Rubio, but that was all. For most people, he doesn’t inspire the sort of excitement or devotion that Trump does, and that’s because he is a little too polished, too scripted, and too much the career politician (which of course is exactly what he is). Bershidsky went on to say of both Cruz and Rubio:

They try too hard, and they fail to connect on a human level.

The explanation for Rubio isn’t winning may be as simple as this: he hasn’t been campaigning enough in the early states to generate strong support there, he has been relying on a more impersonal, long-distance approach to the campaign than most of his rivals, and when he does show up in the early states he isn’t all that good at retail politics. Add in his other weaknesses, including his unappealing message of perpetual meddling in foreign conflicts, and you’ve got a recipe for a bad candidate.