In case you missed it, Lawrence O'Donnell made a pretty compelling case for why Sarah Palin, despite the "movie" and time spent in Iowa, is not running for president. His best argument, that Roger Ailes actually did a good job finding out in advance who was running and suspending those who were (Gingrich and Santorum), while letting those who weren't running (Huckabee and Palin) stay on board. I hadn't thought of that before, and it certainly makes good sense. Say what you want about Roger Ailes, but he is no one's fool.
Here's the full video of O'Donnell explaining why Palin isn't running.