The job of federal judge for the Eastern District of North Carolina has been vacant for more than eight years, one of the longest vacancies of 83 on the federal bench around the country. Last June, President Obama nominated Jennifer May-Parker, a federal prosecutor, for the position, but she hasn’t even received a vote in the Senate Judiciary Committee because Richard Burr, the state’s Republican senator, is blocking her.

The strange part is that Mr. Burr himself recommended her for the seat in 2009. But now he’s changed his mind and won’t say why, exploiting an archaic Senate tradition to make sure Mr. Obama can’t fill that vacancy.

That tradition, known as the blue slip, gives senators the ability to block any judicial nomination in their state, no explanation necessary, before it even reaches the stage of a committee hearing — never mind the Senate floor. There’s no formal rule enshrining this tradition, and the committee’s chairman, Senator Patrick Leahy, a Democrat of Vermont, could end it tomorrow. But he has inexplicably clung to the practice, preventing worthy nominees from being confirmed and allowing petty Republican politics to reduce Mr. Obama’s influence on the bench.

If a home-state senator won’t return a blue piece of paper agreeing to a judicial nomination, Mr. Leahy won’t give the nominee a committee hearing or a vote. It’s a form of senatorial courtesy that goes back to 1917 or so, giving senators an anti-democratic power never contemplated in the Constitution.