SOUTER, OBAMA, AND THE COURT…. When Supreme Court Justice David Souter didn’t hire clerks for the next term, that should have been a pretty big hint.

Justice David H. Souter plans to retire at the end of the term in June, giving President Obama his first appointment to the Supreme Court, four people informed about the decision said Thursday night.

Justice Souter, who was appointed in 1990 by a Republican president, the first George Bush, but became one of the most reliable members of the court’s liberal wing, has grown increasingly sour on Washington and intends to return to his home state, New Hampshire, according to the people briefed on his plans. One official said the decision might be announced as early as Friday.

The departure will open the first seat for a Democratic president to fill in 15 years and could prove a test of Mr. Obama’s plans for reshaping the nation’s judiciary. Confirmation battles for the Supreme Court in recent years have proved to be intensely partisan and divisive moments in Washington, but Mr. Obama has more leeway than his predecessors because his party holds such a strong majority in the Senate.

A month ago, Supreme Court Justice Ruth Bader Ginsburg said President Obama would “surely” be able to choose a new justice “soon.” Looks like she was right. It will be the first vacancy under a Democratic president in 15 years.

A few angles to consider this morning.

Why is Souter stepping down?

Souter, 69, clearly never enjoyed life in D.C., preferring quiet seclusion in New Hampshire. The Washington Post‘s report noted, “A friend who ran into him last summer in Concord said he was surprised by just how strongly Souter spoke about wanting to leave Washington. ‘He said, ‘If Obama wins, I’ll be the first one to retire.’”

Will this change the balance of the high court?

That’s highly unlikely. Souter is one of the court’s more progressive voices, so Obama is poised to replace one liberal with another. The key, however, is age and longevity — Obama may choose a youthful justice, who can be a progressive voice for decades to come.

Who’s likely to get the nomination?

It’s obviously very early — NPR broke the story just 10 hours ago — but speculation is already focused on a handful of names. Some of the leading contenders include federal appeals court judges Sonia Sotomayor and Diana Pamela Wood, Solicitor General Elena Kagan, and Georgia Chief Justice Leah Ward Sears. The early buzz is focused heavily on Sotomayor, who would be the Supreme Court’s first Hispanic justice.

Salon republished a list of possible nominees this morning, as did ScotusBlog’s Tom Goldstein. Sam Stein has a few replacement possibilities as well. (You’ll notice, of course, that there’s quite a bit of overlap among the lists.)

What should we expect from the confirmation hearings?

With the Democratic caucus at 59, chances are pretty good that Obama’s nominee will get confirmed. How Republicans will act, however, is less clear.

As far back as November, literally just a few days after the election, Arizona Sen. Jon Kyl (R) the second-ranking Republican in the Senate, threatened to filibuster any of Obama’s Supreme Court nominees he considered insufficiently conservative. That was 11 weeks before Obama was even inaugurated.

With this in mind, and given the GOP freak-out over uncontroversial cabinet nominees like Kathleen Sebelius, a severe Republican temper tantrum is likely, no matter who the president nominates. If for no other reason, the minority party will see some value in working the base into a frenzy of hot-button cultural issues.

Just when it seemed the political world couldn’t get any more interesting, one more huge task is added to the president’s to-do list.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.