Justice David Souter will leave the Supreme Court at the end of this term, somewhat unexpectedly, at the relatively young age of 69.  Expect much wailing and gnashing of teeth by conservatives over Souter’s potential replacements, but the real problem falls on Barack Obama.  Despite his appointment by George H. W. Bush, Souter reliably stuck to the liberal side of the court, and his surprise retirement gives Obama little chance to change the court.  It does provide him with a raft of headaches, however:

Souter, 69, hails from the court’s relatively liberal branch, so his retirement is unlikely to represent a deep shift in the balance of power on the court, but rather a renewal of the left end of the bench.

Obama will face competing imperatives in replacing him, including the pressure to appoint the first Hispanic to the Supreme Court and his own ties to prominent legal academics beginning with his years at Harvard Law School.

Obama also is likely to face pressure to add a woman to join the court’s lone remaining female jurist, Ruth Bader Ginsburg. Several names emerged quickly Thursday night, including federal Judge Sonia Sotomayor of New York and Elena Kagan, Obama’s solicitor general.

Either way, Obama should have wide latitude is picking who he wants to replace Souter. The recent switch of Sen. Arlen Specter from Republican to Democrat could account for a filibuster-proof 60-vote majority, should Minnesota’s Al Franken be seated as expected.

The gnashing of teeth gets its best representation by Bench Memos blogger Ed Whelan, excerpted at The Corner:

[I]n coming years, Souter’s replacement may well provide the fifth vote for:   — the imposition of a federal constitutional right to same-sex marriage; — stripping “under God” out of the Pledge of Allegiance and completely secularizing the public square; — the continued abolition of the death penalty on the installment plan; — selectively importing into the Court’s interpretation of the American Constitution the favored policies of Europe’s leftist elites; — further judicial micromanagement of the government’s war powers; and — the invention of a constitutional right to human cloning.   American citizens have various policy positions on all these issues, but everyone ought to agree that they are to be addressed and decided through the processes of representative government, not by judicial usurpation.  And President Obama, who often talks a moderate game, should be made to pay a high price for appointing a liberal judicial activist who will do his dirty work for him.

All true, but all would have been true with Souter as well.  What’s more, Souter’s retirement comes unusually early for a Supreme Court justice.  Most of them hang on until their late 70s and early 80s.  The liberal wing of the court could easily have had Souter on the bench for another 15 years, providing everything Whelan notes here.  The story for conservatives here is one of lost opportunity; had we fielded a Republican candidate who could have beaten Obama (assuming anyone could), we might have gotten real change on the court — or perhaps Souter would have just postponed his retirement.

Obama’s headaches come from this same dynamic.  He will face many competing pressures in selecting a replacement.  Supreme Court picks are high-profile affairs, and this will test Obama far more than his previous appointments — many of which have been disasters, like Tim Geithner, Tom Daschle, and the rest of the tax-evaders and lobbyists he’s picked.  Hispanics will want a representative voice on the court, and women will want to gain back the second seat that they lost with Sandra Day O’Connor’s retirement.  Blacks might expect Obama to appoint another African-American.  Meanwhile, in the Senate, Obama will be expected by some to play the bitter partisan game that has existed ever since Ted Kennedy kneecapped Robert Bork, and expected by others to pick someone in the middle ground to end those games.

The biggest tension will come from the far-Left activists of Obama’s party.  They’re losing a stalwart.  They can’t afford to have Souter replaced by a middle-ground justice who may not vote as reliably liberal as Souter.  In fact, that will be Obama’s problem for all of the likely retirements on the Court — Ruth Bader Ginsburg and John Paul Stevens.

Based on Obama’s appointments thus far, expect a mediocre candidate that will be just middle enough to get a few Republicans on board.  Don’t expect it to go quietly, but the Republicans probably won’t stage any extraordinary action to block it, unless something arises like tax problems or other issues that rise to incompetence or corruption.  That’s actually the way presidential appointments should be handled, as elections have consequences.  After the dust settles, the court will be in exactly the same position as it is now, but in the meantime the GOP will have had an opportunity to show Obama as no post-partisan moderate but as a liberal idealogue.  Elections do have consequences — and so do appointments.

Update: Michelle profiles the three leading candidates.  Gird your loins, indeed.