Sen. Susan Collins is in the center of a showdown between the White House and Senate Republicans over judicial nominations.

It’s taking place over the U.S. Court of Appeals for the D.C. Circuit, which has been described as the most important court that no one has heard of.

This court has the final say on complex regulatory questions, affecting environmental policy, health and safety issues, and financial regulations. The caseload for its judges has grown steadily, from 119 per judge in 2005 to 188 today. A slowdown in this court slows down the whole government.

You would expect that vacancies on this court would be filled promptly. But that is not the case.

Earlier this year, Republican senators (including Collins) filibustered a nomination for a vacancy on the court until the candidate withdrew. After the nomination of Sri Srinivasan was confirmed that week, one of four vacancies was filled. But there are still three more to go.

Now some Republican senators, again including Collins, are proposing stripping those seats from the court completely. They argue that the court is too big already. They say the court’s caseload does not compare with what is handled in other circuits, without acknowledging that the kind of case the D.C. Circuit hears can be more time-consuming than the ones other judges see.

This is a move that would freeze in place the current political makeup of the court, which favors Republicans. With Srinivasan’s confirmation, the court will have four judges nominated by Republican presidents and four nominated by Democratic presidents. The balance shifts, though, when you count five senior-status judges who continue to hear cases that were nominated by Republicans against only one senior-status Democrat (a Jimmy Carter nominee). It’s easy to see why Republicans would want to hold on to their advantage.

But that’s not the way to do it. The Republicans should not try to win with procedural maneuvering what they could not get at the polls.

The bill to strip the seats from the court has little chance of getting through the Senate, but the more pressing question is whether Republicans would filibuster nominations when they are made. That could be soon, as reports from the White House are that the president plans to put forward three nominations at once, in order to bring the court back to full strength.

Collins and the other Republicans should ask tough questions of these nominees. And if they find them to be unsuitable they should vote against them.

But they should not filibuster these nominations. The Senate should be doing the people’s business, not blocking it.