The number of vacancies on the nation’s federal courts has reached an astonishingly high level, creating a serious shortage of judges and undermining the ability of the nation’s court system to bestow justice.

Of 856 federal district and circuit court seats, 85 are unfilled — a 10 percent vacancy rate and nearly double the rate at this point in the presidency ofGeorge W. Bush. More than a third of the vacancies have been declared “judicial emergencies” based on court workloads and the length of time the seats have been empty. By far the most important cause of this unfortunate state of affairs is the determination of Senate Republicans, for reasons of politics, ideology and spite, to confirm as few ofPresident Obama’s judicial choices as possible.

Numbers compiled by the Senate Judiciary Committee tell the story. Mr. Obama’s nominees for seats on federal courts of appeal, the system’s top tier below the Supreme Court, have waited an average of 148 days for their confirmation vote following the committee’s approval, more than four times longer than Mr. Bush’s nominees. For Mr. Obama’s nominees to federal district courts, the average wait time has been 102 days, compared with 35 days for Mr. Bush’s district court choices.

The prestigious and important United States Court of Appeals for the District of Columbia Circuit offers a particularly striking example of Republican obstructionism. The 11-seat court rules on most appeals from federal regulatory agencies and has exclusive jurisdiction over national security matters. It has four vacancies; the last time the Senate confirmed someone to the court was 2006.