The best candidate politically would probably be Hispanic.  Hispanic voters both (a) are more politically independent than black voters and therefore more in play in the election, and (b) historically vote in low numbers.  In that sense, the ideal nominee from the administration's perspective in these circumstances is already on the Supreme Court:  Sonia Sotomayor, the Court's first Latina.

On the other hand, I think the President personally will be very tempted to appoint a black Justice to the Court, rather than a second Hispanic.  His historical legacy rests materially on advancing black participation and success in American politics.  The role Thurgood Marshall previously played in that effort is inescapable.  The President likely sees value in providing a counterpoint to the Court's only black Justice, the very conservative Clarence Thomas.

For those reasons, I think the President will pick a black nominee.  I've long said that the most likely candidate for the next Democratic appointment was California Attorney General Kamala Harris.  She is fifty-one.  A female nominee has significant advantages as well.  That is particularly true for the candidacy of the likely Democratic nominee, Hillary Clinton.  For reasons I've discussed elsewhere, I think her nomination is difficult to oppose ideologically, given her history as a prosecutor.

If Harris wanted the job, I think it would be hers.  But I don't think she does.  Harris is the prohibitive favorite to win Barbara Boxer's Senate seat in the 2016 election.  After that, she is well positioned potentially to be president herself.  If nominated, she would have to abandon her Senate candidacy and likely all of her political prospects.  So I think she would decline.

Attorney General Loretta Lynch, who is fifty-six, is a serious possibility.  But she would likely have to recuse from her job, leaving that position open indefinitely.  I also think that the Republicans would have an argument that the attorney general's position shouldn't be left open.

No other black woman immediately comes to mind as a nominee, though I haven't researched the question in some time.  But there is an obvious black male:  Paul Watford, an Obama appointee to the Ninth Circuit.  Watford is in his late forties.  He is well respected and reasonably well known in Democratic legal circles.

Watford was confirmed by the Senate in 2012 by a vote of sixty-one to thirty-four, which is a filibuster-proof majority.  Nine Republicans voted in favor of his nomination.  That gives the Administration considerable ammunition to argue publicly that Republicans, by refusing to process the nomination, are blocking someone who is recognized to be qualified.

Logistically, the fact that Watford was vetted so recently also makes it practical for the president to nominate him in relatively short order.  There is some imperative to move quickly, because each passing week strengthens the intuitive appeal of the Republican argument that it is too close to the election to confirm the nominee.  Conversely, a nomination that is announced quickly allows Democrats to press the bumper sticker point that Republicans would leave the Supreme Court unable to resolve many close cases for essentially "a year."

The court is not yet halfway through the 80 or 90 cases it deals with each term, but many of the most contentious have already been heard. Normally, justices meet the week a case is argued, and vote on the outcome. So they have most likely already voted on pending cases on apportionment and affirmative action, for example. But weeks or months can go by while the justice assigned the opinion circulates drafts. Any justice can change his or her vote at any point during that process, and often does. It's all very hush-hush, so there is no way to tell how far along the cases Scalia heard are in the pipeline.

There is no constitutional provision, no case law and no official policy about what the court should do with cases that have been argued and voted on when a justice dies. If the vote in a case that hasn't yet been handed down was 5 to 4, as one might expect with these controversial rulings, can Scalia cast the deciding vote from beyond the grave to change the way America chooses every legislature in the land or integrates its public universities? A court that cares about its image and constitutional role will not rule in the name of a majority that counts on a dead justice, especially on the core issues of American social life. Such posthumous decisions are so unprecedented they would make Bush v. Gore look like responsible judicial behavior. Chief Justice John Roberts, who in matters entirely internal to the court like this wields some extra power, is known for his concern for institutional prestige, and he would be right to weigh in against issuing opinions based on what Scalia did in past conferences.

So in the cases that Scalia was already a part of, what's most likely is that the court will do what it has done in the rare, similar circumstances in the past, when important cases like abortion were argued and the personnel on the court changed or where a predictable swing justice was out sick: They will order the cases argued again and voted on again.

Of course, the justices will also continue to hear future arguments, but upcoming closely decided cases -- such as the abortion case out of Texas also widely predicted to lead to a 5 to 4 vote -- will now be tied, 4 to 4. In this term's contentious, controversial docket, split decisions are inevitable. The court can reargue the pending cases and hear the upcoming ones, but they will be too divided to decide anything truly sweeping. Unresolved cases will stack up.

SNIP

But the GOP might soon reconsider if they see the implications of refusing to allow Obama to replace Scalia: A divided court leaves lower court rulings in place. And the lower courts are blue. Nine of the 13 U.S. Courts of Appeals have a majority of Democratic appointees. That means liberal rulings conservatives were hoping the Supreme Court would overturn remain law.

SNIP

Two-thirds of the people in the country live in blue-court America.