A new study from the nonpartisan Congressional Research Service [pdf] quantifies the extent to which Senate Republicans have been stalling President Obama’s judicial nominees. Through this persistent obstruction, Senate Republicans have kept the chamber mired in gridlock, thrown the federal courts into an historic vacancy crisis, and prevented President Obama from restoring ideological balance to a system still dominated by George W. Bush nominees.

The study finds that President Obama’s judicial nominees – including those with no partisan opposition – face extraordinary wait times for simple yes-or-no votes from the Senate.

CRS notes that “President Obama is the only one of the five most recent Presidents for whom, during his first term, both the average and median waiting time from nomination to confirmation for circuit and district court nominees was greater than half a calendar year.” In particular, the study notes, the wait times for district court nominees – whose decisions do not bind other courts and who have historically been approved quickly and without controversy – have shot up in the past four years:

Where President Obama’s judicial nominees face the greatest delays is between approval by the Senate Judiciary Committee and a vote from the full Senate. Because the Senate must have unanimous consent or invoke cloture to hold an up-or-down vote, senators in the minority can quietly filibuster judicial nominees for months without giving a reason for delaying the votes. For instance, Robert Bacharach of Oklahoma, who was nominated to a seat on the Tenth Circuit Court of Appeals, was forced to wait nine months for a vote from the full Senate, despite the fact that he was supported by both of his home state’s conservative Republican senators. In the end, he was confirmed unanimously.

Perhaps the starkest example of Republican obstruction under  President Obama is the gridlock that completely unopposed judicial nominees have faced. CRS finds that President Obama’s unopposed district court nominees have waited nearly three times as long for a Senate vote as did President Bush’s and nearly six times as long as President Clinton’s. His unopposed circuit court nominees have waited over four times as long as President Bush’s and seven times as long as President Bush’s.

It’s important to note also that many more of President Obama’s nominees would count as unopposed – making these numbers even more dramatic — if Republican Sen. Mike Lee of Utah hadn’t spent a year opposing every one of President Obama’s judicial nominees in protest of a completely unrelated issue.