How important is likeability for a presidential candidate?

I don’t know how many Bookwormroom readers follow American Idol, but the American Idol crowd is all abuzz at the voting out of Pia Toscano last night. Ms. Toscano has an amazing voice, probably the best of all of the candidates. Nearly everyone is shocked that she is gone. I’m not. She may have been the best vocally, but she was the least likeable of all of the candidates. She may have just been uncomfortable on the big stage, but she always looked a bit stiff, like she held herself aloof from the other candidates.  Obviously, likeability is a huge factor when people pick up their phones to vote for an Idol.

One would think the same would hold true for politicians.  And, I suppose, most of our presidents in recent years have been likeable — Ike, JFK, Reagan, Clinton, Bush II, Bush I in later years, though he was very stiff at first.  But how does one account for presidents like Nixon, Carter and Obama who don’t appear to have a warm, likeable bone in their bodies? 

More significantly, looking forward to 2012, how important is likeability for the candidates who will be running then, and which candidates hold the edge (and which are at a disadvantage) in this regard?