I’ve been rolling the idea of Caroline Kennedy as a New York Senator around in my head going back and forth between, “Why not?” and “Why her?”

Other than the fact that her last name is Kennedy (well, actually it’s Schlossberg), why would she be a good senator?

On the qualification thing, that’s always subjective. She has a law degree, is a published author on constitutional law, oversees charitable foundations and works to make public education better in New York City. The bigger question the Democrats need to focus on is will she be a good campaigner? She gave a nice speech at the Democratic Convention about Barack Obama and her uncle, Ted Kennedy, but nice isn’t going to cut it in the Senate or on the campaign trail when things get tough.

If Caroline gets the Hillary gig, then she has to run in 2010 to stay in the Senate for the remaining years of the term. I could be wrong, but I really have to wonder if she’s got the fire in the belly and sharp enough elbows to survive a New York campaign, not to mention to the committee rooms of the Senate.

Caroline Kennedy is smart and giving and lovely in the way that so many women we admire are, but given the state of politics today, that’s not enough, even when it’s attached to the Kennedy name, to take on whatever pit bull the GOP would be sure to throw at her when she’s actually got to work for the Senate seat.

Let’s face it — Hillary didn’t have an easy time getting elected the first time around. She worked her tail off with the grand tour of New York State as she convinced people she would advocate tirelessly for them. And she did.

Finding a replacement for Hillary Clinton shouldn’t be about entitlement, but it’s feeling a little bit that way. I’d rather that it be about someone who is passionate enough when it comes to Democratic issues that they won’t be afraid to face down the GOP.

Caroline Kennedy and I have something in common. We’ve faced the big 5-0 recently and are doing fine. But it’s no time to look at a very important Senate seat and have it be part of a mid-life crisis plan.

It’s OK if we don’t have a Kennedy in the Senate — the republic will survive that. But we do need someone in that slot who will fight hard to keep it in 2010. And I really wonder whether Caroline Kennedy can do that.