It's fair to say no matter whom the president picks to replace one of the court's most conservative justices, he'll have a fight on his hands to get that person confirmed by the Republican-controlled Senate so late in his presidency.
But depending which type of Supreme Court candidate he nominates, Obama could make the confirmation fight a little easier or much more difficult for everyone involved — for him, for the nominee and for Senate Republicans. Obama could choose a consensus candidate or decide to play politics with his pick and roll the dice that his successor will be a Democrat who can pick up the game where he left off.
Here are three types of nominees Obama could choose. All three could potentially lead the confirmation process down very different paths, but their political implications aren't necessarily mutually exclusive.
1. The 'best person' for the job
Or at least, the best person for Obama's definition of the job. And Obama's job description probably includes someone who would vote to overturn "Citizens United," that 2010 Supreme Court decision despised on the left that opened the floodgates of money in politics even further. He'd also probably want a justice who doesn't think the president overstepped his constitutional bounds in expanding deportation relief for undocumented immigrants (a critical case the court is expected to hear this summer).
And of course, Obama would want someone who shares his pro-choice views on abortion.
In other words, the most obvious pick for Obama would be someone who sees the world and the Constitution the way he does. Names that might fall into this category include Massachusetts Gov. Deval Patrick (D) or Paul Smith, who chairs an appellate and Supreme Court practice and would be the first openly gay justice.
Confirmation path: Not likely. It's safe to say that someone like this would not survive a confirmation vote in the Senate (if Republicans ever even brought it up for a vote). So Republicans vote down Obama's preferred nominee, and that's that. Game over until the next president and next Congress.
2. The 'best person' to get the job
There's a phrase in Washington we don't hear a lot — compromise. But it could happen if Obama decides to compromise on his perfect candidate and instead nominate someone whom he can live with and whom Senate Republicans can live with too.
Perhaps someone like a dynamic moderate Republican governor or even senator with pro-choice credentials. Names in this category might include Nevada Gov. Brian Sandoval (R), a pro-choice, pro-immigration-reform former U.S. District Court judge who is also liked among Republicans.
Confirmation path: A justice no one likes but enough people can agree on gets confirmed. A major caveat here: If Obama goes down this route, it would be a difficult tight-rope walk to find someone both he and Republicans find palatable enough to agree on. The very basic litmus test of whether abortion should be legal is probably a non-starter for both sides (which could rule out someone like Sandoval).
And Obama, by nature of his executive actions and the fact he has less than a year left in office, is perhaps more toxic than ever in conservative circles. So whomever he nominates will probably be viewed automatically with suspicion by Republicans.
3. The 'best person' to give Democrats back the Senate
Here's where things could get overtly political. Obama could decide the first two options are so unlikely to succeed that he's going to punt to the next president (hoping it's a Democrat) and give him or her the best chance to get a nominee through.
Taking such a bet makes sense when you look at the political landscape Obama is facing to get his nominee confirmed. He is stymied by the simple fact that Republicans have controlled the Senate since 2015 and can simply decide not to bring up his nomination for a vote for a whole year.
But that dynamic could change in November, when Democrats have a chance of taking back the Senate. Republicans are defending 24 of the 34 seats in 2016, many of them in potential swing states where the 2016 race could play a big role in deciding how the rest of the races go.
So Obama could decide to nominate a message candidate instead, someone who rallies the Democratic base enough that it puts vulnerable incumbent Senate Republicans in a politically awkward situation. Do they vote no with their party and risk alienating a sizable chunk of swing voters who may already be put off by Republican presidential candidate Donald Trump, or do they go out on a limb and support Obama's nominee?
"I'm sure every Republican senator up for reelection would give anything not to have to cast a vote about a Supreme Court nominee," said Russell Wheeler, a judicial expert with the Brookings Institution. This quandary is particularly acute for senators running in states that voted for Obama in 2012, such as Ron Johnson (R-Wis.), Kelly Ayotte (R-NH) and Rob Portman (R-Ohio).
The politics of this are so sensitive that just about any nominee Obama likes could fit into this category.
Confirmation path: Who knows? Does Obama's pick rally his base enough to help boot out Republican senators and elect a Democrat to the White House? Or does it backfire, and we enter 2017 with Republicans controlling both chambers of Congress and the White House?
It's safe to say whatever path he chooses is a high-stakes gamble, and we may not know who won until November.