Secretary of State Clinton? I Just Don't Get It

For the life of me I just don't understand why a) President-elect Obama would want to choose Hillary Clinton as Secretary of State and b) she would accept the post.

Why would Obama want to tarnish his brand new administration with the Clinton soap opera of Monica, Whitewater, Vince Foster, Marc Rich and company when he could start fresh with an entirely new team? And why would he want a mortal enemy like Hillary who is probably at this very moment plotting her comeback strategy for 2012, inside his administration, leaking to the press and undermining him? I thought he put the Clintons away for good. He seems too smart to do something like this.

Then again I don't understand Hillary's reasons either. Why would she want to take the post of Secretary of State, not exactly traditionally a stepping-stone position to the Presidency when she could stay in the Senate, knock off Harry Reid and become Majority Leader and be in good shape either for a rematch against Obama in 2012 or a run at Joe Biden in 2016.

Hey, they can get hitched if they want to, but it just doesn't make any sense to me.