Sarah Palin is the biggest advertisement why Sarah Palin should not run for President.
An out-spoken pundit, she does not possess the skills to create coalitions, to compromise, and to communicate with the other side, a necessity, even within the Republican Party, riven with diverse factions of differing agenda having varying layers of common ground and inflexibility.
A vocal critic of President of Obama, Palin is a lightning rod of dissent and dist ate. Independents do not like the woman, and their vote is crucial for anyone who wants to be the next President of the United States. Her unfavorability, played a significant role in the defeat of Republicans in swing states and heavily Democratic bastions, like Carly Fiorina for the U.S. Senate seat in California.
She is strident to the point of infecting her rhetoric with herself, a major distraction which has already set back the Republican Re-Revolution to stop the Statist Liberal Agenda. She campaigned aggressively for Christine O'Donnell in Delaware, a t-to-1 Democratic state which saw the primary loss of a shoo-in (moderate) Republican to another established Liberal. Her personal animosities frustrated the upstart victory of Alaskan Joe Miller, undermining the GOP's attempt to replace a moderate with a more reliable conservative voice in the U.S. Senate.
Palin is controversial and outgoing, both great traits for radio talk-show host, columnist, or motivational speaker, are not fitting for a presidential candidate, who must ingratiate herself to a very open, skeptical public.
Of course, there are also personal forays into media, like her failed reality TV show, and her gushing approval of daughter Bristol's scandalous self-exploitation on "Dancing with the Stars". Does the United States really want a president who would stoop low to make a show of herself or to make a profit. If those concerns seem petty, consider her sudden resignation as Governor of Alaska, a commitment which she tossed aside because of ethics allegations which, she claimed, would have cost her and the state too much. Those allegations were quickly resolved, at any rate, undermining any justification on the part of Governor Palin for abandoning the office to which she was elected.
These issues should be more than sufficient to discourage Sarah Palin from running for President.