I have just written this piece for Slate. It begins:

Headlines blare that a battle looms over the nomination of a replacement for Supreme Court Justice John Paul Stevens–a battle, likely to get ugly, in which Republicans have not ruled out a filibuster. Don’t believe it. Insiders like Tom Goldstein and Nina Totenberg expect no real battle, barring some unforeseen revelation about President Obama’s nominee.
Obama is using the Supreme Court to position himself for re-election in 2012 not with the Justice Kagan-Wood-Garland choice of 2010 but by raising the specter of the retirement of 76-year-old Justice Antonin Scalia after the 2012 presidential election. The court’s recent Citizens United decision, striking down limits on corporate election spending, has been deeply unpopular, providing an opening for him to run against the increasingly conservative Court. It wouldn’t hurt the president if the court soon decided a few more 5-4 unpopular decisions, so that the stakes of a conservative Justice retirement are ever clearer to Obama’s supporters on the left.

It concludes:

Last year the Court came pretty close to striking down a major portion of the Voting Rights Act: With new voting rights cases on their way, a 5-4 decision striking the law down could come before 2012. There could also be new conservative rulings on abortion, gun control, and even the power of Congress to pass health care reform. Each conservative ruling before 2012 could help President Obama.
Kennedy and the Court’s four stalwart conservatives–Alito, Roberts, Scalia, and Thomas—will almost certainly remain through Obama’s first term. But things get much more uncertain after 2012. By 2016, Justice Scalia will turn 80 and Justice Kennedy will turn 78. It is certainly possible that they will stay past the 2016 elections–after all, Justice Stevens is pushing 90–but who knows?
President Obama’s political task, three years from now, will be to convince the country that he, not a Republican president, should make that potential appointment. The point isn’t to show that he would move the Court leftward if re-elected in 2012–he’d probably be better off sending more moderate signals, which is another reason not to expect him to choose a strong liberal to fill Stevens’ seat. Obama should instead stress that if a Republican wins in 2012, Scalia and Kennedy will probably retire. That would give the new Republican president the chance to entrench the five-justice Republican majority for decades–and to cement it, by replacing Kennedy with a wholly reliable right-wing vote. That’s the Supreme Court script for the Democrats in 2012.