There are plenty of sentimental arguments for Caroline Kennedy to be given Hillary Clinton's Senate seat. (I generally find them ridiculous, but they're persuasive to some.) But the primary hard-nosed, no-nonsense argument I've run across is that this will be a tough seat to hold onto (I'm not entirely convinced), so the Democrats need someone in it who can rise to the challenge of back-to-back re-election races in 2010 and 2012. Kennedy, it is said, will be able to do this, because she will be able to raise the $70 million that some speculate will be required.
Leave aside, for the moment, the fact that having rich friends and experience raising philanthropic dollars is very different from raising tens of millions in increments of $2,300 or less. And also leave aside the fact that any sitting Democratic senator in New York is going to be able to raise a great deal of money. In other words, grant the (to my ears, questionable) proposition that Kennedy will be able to significantly outraise anyone else who is appointed to that seat.
One is still left with the fact that getting elected (or, in this case, re-elected) to the Senate requires a great deal apart from money. Yes, fine, Bloomberg effectively bought his office, as did Corzine. But both are ambitious, ego-driven, status-hungry personalities in a way that Kennedy (to her personal, but probably not political, credit) is not. More to the point, successful politicians who purchased their offices are still the exception.
If you're choosing a senator to face the exceptional challenge of back-to-back races in 2010 and 2012, do you really want it to be someone who has never run for any elective office at all? Who's never held a press conference before a group of political reporters? Who's never participated in a public debate with an opponent? Can Kennedy take a punch? Can she throw one? We don't have any real idea and, in all likelihood, neither does she.
Politics requires all kinds of grubby chores and compromises and impositions that some people are willing to endure in order to hold office, and others--however smart, or decent, or public-spirited--are not, and Kennedy has, up until very, very recently given every possible indication that she is in the latter category. It seems to me that if you think Clinton's seat will be a hard one for a Democrats to hold onto (and, again, I'm somewhat skeptical), that's an argument against Kennedy, and in favor of someone (and there is no dearth of options) who has demonstrated a willingness and ability to do all the little things that make life in politics so distasteful.
Indeed, my guess is that the common perception that Kennedy would be a mediocre senator but a great senatorial candidate is exactly backward. I have little doubt that she's knowledgeable and diligent enough to be a perfectly adequate senator. But I have serious doubts that she has the skills and temperament to run hard, back-to-back races against determined opposition.