That's part of a growing trend of politicians who are leaving office when they're still young enough to do something else. Ask them why, and you usually get some variation of this answer: They're just tired of dunning people for money.
When Mr. Smith goes to Washington these days, he has to spend a lot of money to get there - his own and whatever he can beg and borrow from friends and people he doesn't even know. Once he gets there, he thinks it's all behind him, but it's only the beginning.
The price of campaigns keeps going up, and he must begin raising more money immediately to scare off challengers. So he spends his nights running from one fund-raiser to another, and every weekend raising money back home.
Through the fog of perpetual jet lag, it dawns on him one day that this isn't a very interesting way to spend your life.
That this is what politics has become should give all of us some pause, even those who favor term limits.
When holding public office becomes so uninteresting and so unappealing that fewer and fewer people want to fool with it for very long, we've got a real problem.