"Those of us who have been here a long time realize that this is a double-edge sword: Sometimes you have a Democratic president, sometimes you have a Republican president," Leahy said to a group of regional reporters. "You ought to fight over whatever you want but judges should be treated really differently."
Lee has voted against all of President Barack Obama's nominees this year, be they administrative or judicial, to highlight his opposition to the way the president placed Richard Cordray at the head of the new Consumer Financial Protection Bureau.
Obama said he used his authority to make recess appointments. But Republicans like Lee argue the action was unconstitutional because the Senate wasn't in recess, since it was holding quick sessions every few days.
"If a Republican president had completely ignored the Senate and taken power that did not belong to him, I imagine Sen. Leahy may have seen things differently," Lee said. "It is unfortunate that he sees it as a partisan issue when it is really a matter of defending the Senate's constitutional role."
Sen. Jim DeMint, R-S.C., is the only Republican who has joined Lee in his protest, while others, such as Sen. Orrin Hatch, R-Utah, say the fight is best waged through the courts.
The dispute is just part of a long-standing partisan fight over the speed of confirmation votes. Democrats sought to highlight "Republican obstructionism" this week by forcing votes on 17 noncontroversial picks, including that of David Nuffer, whom Obama chose for one of the two openings on the Utah District Court.
Republicans argued Democrats were trying to divert attention from rising gas prices and a slow economic recovery.
On Wednesday, Democratic and Republican leaders avoided the showdown and agreed to vote on most of these nominees by May 7, holding a few votes each week. As a result, the Senate is expected to vote soon on Nuffer's nomination.
The Administrative Office of the U.S. Courts considers the opening in Utah a "judicial emergency." The state has only three full-time federal judges; it should have five.
Lee won't say whether he will vote for Nuffer, whom he supports, or vote against him in protest.
But he said the agreement hasn't changed the way he feels or his plan of action. "My objections to what the president has done remain what they are," he said.