I think that's a good call. I have nothing against Caroline Kennedy. She seems very nice and smart. But politics is a profession, like medicine, or journalism, or banking. You get better with practice, and she has not practiced it. I know she's been around politics for her entire life, but there is no substitute for being the person who makes the decision.
We don't know specifically why she withdrew - she cited "personal reasons," but this brings up another point. If you are considering being in public life, your life will be scrutinized to a far greater extent than it would be if you are in private life. If she hasn't been considering taking public office until now, she probably has not been as careful as a politician in how she handles, for example, her personal finances. So she may have issues like unpaid taxes or a nanny that wasn't perfectly legal. Timothy Geitner had those issues, but he managed to get past them because he is obviously highly qualified to be Secretary of the Treasury. His resume outweighs a few mistakes. To be perfectly fair, I have no idea whether or not Caroline Kennedy had any such issues. But she doesn't have a resume as public official, so she doesn't have something to fall back on if things turn ugly.
A final clue as to why she backed out may be found in the saga of her decision to withdraw. Apparently there was some wavering on her part, which of course is not a good quality for a politician. Someone close to David Patterson, governor of New York, put it well:
"The fiasco of the last 24 hours reinforced why the governor never intended to choose her"In politics, you can hesitate, consider, equivocate, procrastinate, maybe even waffle, in certain situations. But only some special situationsDeciding on whether or not you want a particular office is not one of those situations. Once you go for it, you cannot waver.