As in so many things, both parties have a record of treating presidential nominees unfairly and undermining the process of staffing the government — but Republicans’ hands look particularly filthy right now. It’s as though they are encouraging Senate Majority Leader Harry M. Reid (D-Nev.) to smash the filibuster.

The Capitol (J. Scott Applewhite/Associated Press) The Capitol (J. Scott Applewhite/Associated Press)

GOP senators on Thursday blocked perhaps the least contentious nominee President Obama could possibly have picked for a spot on the country’s second most important court, the U.S. Court of Appeals for the District of Columbia Circuit. They were not judging Patricia Millett on her credentials or her temperament. In fact, they weren’t really judging her at all. Instead, by their own admission, Millett’s opponents made her the victim of a GOP crusade to limit the size of the powerful court — conveniently enough, right when President Obama has the opportunity to fill three vacant slots.

The D.C. Circuit has always been important. It considers cases related to federal agencies, like the Environmental Protection Agency, and it regularly feeds judges to the Supreme Court. Then it began issuing rulings hostile to Obama administration regulations, and politicians became even more focused on it. Liberals want Obama to take his opportunity to change the ideological disposition of the court. Conservatives want to stop that. Neither side does a good job of even pretending that raw politics aren’t motivating the current fight.

Republicans have tried by claiming that the D.C. Circuit doesn’t need more judges, because it doesn’t take as many cases as other appeals courts do. Sen. Charles E. Grassley (R-Iowa) also argued on Thursday that the court is balanced right now, so the president shouldn’t touch it. Democrats dismiss these claims with numbers of their own, and they point out that Republicans tried to fill the D.C. Circuit when George W. Bush was president.

The big point, though, is that it’s plainly unrealistic of Republicans to insist, suddenly, that a Democratic president must be the one who doesn’t get to appoint judges to open slots on the court. They wouldn’t take that demand seriously if Democrats made it of a Republican president. It’s even worse for Republicans to filibuster any and all nominees because Democrats didn’t agree. Among other things, these moves degrade an already fraying confirmation system that only works if senators exhibit some restraint when it comes time for a president of the other party to pick judges. As the Post Editorial Board noted before the vote on Thursday, there is a fairer way to shrink the court, if it really needs it: “limit future presidents from filling seats that come open in the next presidential term and thereafter.”

Look, anyway, at the consequences of Republicans’ Thursday filibuster. The Senate denied a widely-respected, impeccably qualified and hard-working American the opportunity to serve the public on the federal bench. Republicans haven’t produced any reason strong enough to justify that sorry result.