Many hope, and many others fear, that President Obama will choose a crusading liberal activist to energize the Supreme Court's progressive wing.
Such an appointee might push to expand racial preferences, abortion rights, and especially welfare rights for poor people; to strike down the law barring openly gay people from the military; to recognize gay marriage (which Obama has opposed); to end the death penalty and curtail gun rights (both of which he has supported); to free Guantanamo detainees unless they can be convicted of crimes (which would reject Obama's policy); and much more.
The preceding parentheticals suggest some of the reasons I'm cautiously betting that Obama will choose a moderate liberal who believes in judicial restraint. By this I mean deference to elected officials unless they violate clear constitutional commands or show gross irresponsibility. The lack of such restraint is what I mean by "judicial activism."
A restrained liberal justice might, for example, hope for legislative recognition of same-sex marriage (as do I) but decline to rewrite the Constitution to override the democratic process on the issue by judicial decree.
This is not to suggest that the president will pick a centrist, let alone a conservative. Filling moderately left-of-center Justice David Souter's seat with anyone seen as more centrist would be a stunning abandonment of Obama's campaign stance that would infuriate his liberal base.
But nominating a crusading liberal activist could seriously jeopardize the president's own best interests, in terms of policy as well as politics. And although some of Obama's past statements are seen by critics as a formula for judicial activism, he has also shown awareness of its perils.
As a matter of policy, consider Obama's most important responsibility: protecting our national security from jihadist terrorism and other threats.