Justice Stevens is contemplating retirement from the Supreme Court. Why now? Well, Stevens is a liberal and he’d like to see another liberal justice replace him. Obama is likely to appoint a liberal, so the timing seems right.

Ironically, Stevens originally thought he was a conservative Republican when Gerald Ford appointed him back in 1975. No president can be sure of what he’s going to get from a Supreme Court appointment. That’s why Mr. Stevens’ departure may not be timed so right. This is an election year, and the Republicans are more feisty than ever to rain on Obama’s parade. Would they threaten a filibuster over a liberal nominee? Absolutely. Politics is not about doing what’s right for the nation. It’s about doing what’s right for one’s self, one’s party, and one’s PAC contributors.

Obama doesn’t want to upset independent voters, but he’d also like to fire up his liberal base, which he offended with the watered-down health care bill. In an America where the Tea Party is increasingly more vocal and looking set to hijack the Republicans, perhaps going with the middle-of-the-road would be the best course of action. Let Palin & Co. alienate the middle: Obama & Co. can get a broader majority with the left and that alienated middle. His stature is good: he need only campaign a day for each marginal election to pump up the voters and get them to turn out to support his supporters.

A moderate on the court, however, will not do much to change its conservative nature. That’s why some Democrats are politely asking Justice Stevens to wait another year and retire after the election.