Deep thoughts from lefty E.J. Dionne. It all makes perfect sense now.

First, compared with Palin, Romney is a plausible president. Many conservatives won’t say that publicly for fear of alienating Palin or her followers, but they believe it. Suddenly, Romney’s looking like a bit — or more than a bit — of a technocrat becomes an asset to him.

Second, Romney is a kind of front-runner for the 2012 Republican Presidential nomination, and Palin’s huge presence in the media blocks out alternatives to Romney (notably Minnesota Gov. Tim Pawlenty, who appeared at CPAC today). The media don’t have much time or room for a long list of GOP candidates, and the media obsession with Palin leaves space for only one other candidate. Romney has the best claim on that spot.

Third, I am absolutely convinced that Palin will not run for president, but that it’s in her interest not to say so until the very last moment. Attention is what she needs for all her other enterprises, and being a possible candidate for as long as possible will get her lots of attention. Romney wants her out there as long as possible as his blocking back. This will make it harder and harder for the alternative to him to emerge.

There’s some sense to that. Like it or not, the prefab narrative for the 2012 primaries is Palin vs. anti-Palin, partly because the media wants/needs a moderate opposite their Grim Reaper of “true conservatism” and partly because everyone likes a simplistic binary “hero vs. villain” storyline. Huckabee’s too much like her to qualify as anti-Palin — he’s rural, Christian, and all that other supposedly bad stuff — but Mitt, as a wealthy northeastern child of privilege, fits the role to a T. And of course he’s almost certainly running, so all that’s left to lock in the storyline is for Sarahcuda herself to declare her candidacy. But she has no incentive to do that anytime soon: Like Dionne says, she gets plenty of buzz from the will-she-or-won’t-she speculation, and there’s no point in declaring early when the economy could turn around in a year and start pushing down unemployment, making The One’s reelection all but inevitable. Best to hang back, tease the possibility, and stay out for as long as possible. In fact, if she does decide to run, she has every reason to declare later than usual so that her candidacy comes off looking as some sort of deux ex machina designed to excite a conservative base that’s unhappy with its choices.

Long story short, as long as Palin’s undecided, the primaries will be about her versus Romney, which makes things difficult for Huck, Gingrich, Thune, and everyone else trying to find a niche. Pawlenty has an especially tough challenge since, unlike Huckabee, he doesn’t slide easily into the Palin slot. The fact that he’s northern and not quite as ostentatious about his faith as Palin and Huck makes him more of a rival to Romney as the anti-Palin (his blue-collar cred notwithstanding), although that could change if Huck and Sarahcuda both decide against running, thus leaving the media with a blue-collar/white-collar narrative to cast instead.

An exit question I don’t think I’ve ever asked before: Assuming that Palin did, for whatever reason, decide early that she wasn’t running, whom would she likely endorse? I honestly have no idea.