President Obama and Supreme Court Justice Ruth Bader Ginsburg. (Melina Mara/The Washington Post) President Obama and Supreme Court Justice Ruth Bader Ginsburg. (Melina Mara/The Washington Post)

Sooner or later, there’s going to be another Supreme Court nomination — indeed, if Ruth Bader Ginsburg wants to maximize the chances of being replaced by a justice with similar views, it could be as early as this summer. What can we expect?

Well, to begin with, a filibuster. That’s pretty much certain: Republicans will insist on 60 votes for confirmation. They may not force a cloture vote if the nominee clearly has 60 or more votes, but the target will certainly be 60, not a simple majority.

So the question becomes whether a filibuster can be defeated. Let’s assume the nominee is basically similar to Barack Obama’s first two choices, Sonia Sotomayor and Elena Kagan. In both cases, the objection basically came down to one thing: they were likely to vote with the court’s “liberals” and against the “conservatives.”

Sotomayor was confirmed 68 to 31 in August 2009. Republicans voted against her, 31 to 9. The nine supporting Sotomayor included three who are still senators (Alexander, Collins and Graham) and six who are now gone (Bond, Gregg, Lugar, Martinez, Snowe and Voinovich).

Kagan was confirmed 63 to 37, with Republicans opposing her 36 to 5, and one Democrat — Ben Nelson of Nebraska — breaking ranks. The Republicans for Kagan were continuing Sens. Collins and Graham and the now-retired Gregg, Lugar and Snowe.

What else can we look at? On the Caitlin Halligan cloture vote this year, only one Republican broke ranks: Lisa Murkowski, who voted against both Sotomayor and Kagan but since then lost a primary and won reelection anyway. Murkowski was also, along with Collins, one of two Republican senators to vote for cloture on Chuck Hagel both times and then vote against confirmation — a possible indication she might be open to voting for cloture even if she wouldn’t ultimately back a nominee.

So what does all of this tell us? It may be possible for President Obama to get a mainstream Democratic choice confirmed … but not by very much. It’s hard to find more than five Republicans who might be willing to vote to confirm; I think it’s almost impossible to imagine a nominee similar to Kagan and Sotomayor getting more than, say, 62 votes for cloture. And if Republicans even pick up as few as two seats in 2014, then confirmation under current Senate rules and practices would be extremely unlikely. I’ve seen some speculation that Republicans would only really block a nominee if it was to replace one of the more conservative justices, but there’s really nothing in the voting (or the logic of the situation) to support that.

So, in the event a nomination fell short, what would happen? Democrats could force a live filibuster and hope that outside groups put on pressure to allow an “up or down” vote, but it’s not clear that any Republican would flip if the vote was even higher profile than it already is. Obama could attempt to undermine opposition, which would likely be expressed as some specific complaint about the specific nominee, by rapidly replacing each candidate with another, again to try to pressure a few Republicans to flip. There doesn’t appear to be any way to compromise on the substantive position of the nominee … if Republicans are committed to opposing anyone more liberal than Chief Justice Roberts, then there may not be anyone who can obtain 60 votes from either side.

The one compromise that is possible, however, would be based on the age of the nominee. If Obama sent up a 70-year-old instead of someone in her 50s, then Republicans might be willing to confirm. Other than that, however, it’s difficult to imagine anything other than Senate reform that would budge a committed group of 41 or more Republicans. And it’s very possible that’s what we would have right now — and, again, almost certainly if Republicans gain anything in 2014.