Former Prospect editor Michael Tomasky has some wise words about the likely impact of a Palin candidacy:
So this is where were headed, if she runs, down into this abyss of reactionary sloganeering. And while she may not be the nominee, she's likely to have a huge impact on the race. The other Republican candidates are going to be extremely cautious about taking her on. Not only or even mainly because she’s a woman; more than that, because she has the largest following of any of them among the GOP base, by far. It's a crucial point here that all the leading candidates have histories of apostasy: Mitt Romney on health care, Tim Pawlenty on carbon and the environment, Jon Huntsman on having worked for Obama (and even now Newt Gingrich, having thundered against Paul Ryan's budget). Palin will tear into them, and they'll probably be loath to tear back, because they want her voters after she drops out. So if she’s smart—and that she is, at least in this particular way—she should be able to set the terms of discourse by saying outrageous things and then watching as reporters ask the others whether they agree with her, and they say, out of mortal fear of the base, yes I do.
I think this is all true even if she doesn't run (and I still think she won't). It's not just the size of Palin's base; it's the intensity, and the particular way they feel about her. Like Palin herself, her supporters practice the politics of personal resentment, consumed with real and perceived slights to their tribune from the tundra. They might be OK with eventually signing on to support a candidate who had committed some policy heresy at one time or another, but they will absolutely not tolerate anyone being less than deferential to their Sarah.
And this test -- Are you in Sarah's good graces? Have you genuflected before her properly? -- will continue all the way to November. If there is anything Palin knows how to do, it's keep herself in the news. The nominee (presuming it's not her) will have to pay homage to her over and over and over. And every time he does, he'll lose more votes.
