I propose that Bush should consider nominating Anthony Kennedy to be Chief Justice of the Supreme Court.
The Democrats are clamoring for nominations in the mold of O’Connor. Kennedy, while having a different focus than O’Connor, is just about exactly as conservative or liberal as O’Connor. And, until a third vacancy occurs, Kennedy will be the swing vote on just about every issue, so Kennedy will be the de facto chief of the Supreme Court anyway.
Essentially, it buys Bush a perception of centrism at almost zero cost. The public perception will be of a perfectly balanced court being created by Bush: four liberals, four conservatives, and the Chief Justice as the ideological centrist. And yet, Bush will have steered the court as hard to the right as is presently possible.