The Senate headed closer to a major showdown over President Barack Obama’s picks for the U.S. Court of Appeals for the D.C. Circuit on Thursday following a party-line vote approving Washington lawyer Patricia Millett’s nomination.

Republicans for weeks have voiced opposition to filling any more vacancies on the D.C. Circuit, often considered the country’s most important court second to the U.S. Supreme Court. The Senate Judiciary Committee vote on Millett’s nomination was the first test of how strongly Republicans would oppose Obama’s nominees.

The 10-8 vote was along party lines, with every Republican voting against Millett, an appellate litigation partner at Akin, Gump, Strauss Hauer & Feld. Her nomination now awaits a vote by the full Senate. Republicans appear poised to block it, setting up a showdown that could once again cause Democrats to threaten a historic change to the Senate’s filibuster rules.

A similar threat earlier this month broke the gridlock for several Obama executive branch nominees who had been stalled for months.

During Thursday’s committee hearing, Republican senators insisted that their votes had nothing to do with the qualifications of Millett, who has argued 32 cases before the U.S. Supreme Court. Instead, they said the workload does not justify filling the three vacancies on the 11-member court at this time.

“I have no objection to her, personally,” Senator Orrin Hatch (R-Utah) said before the vote. “I don’t know enough about her but I think she’s probably well-qualified.”

Senator Jeff Sessions (R-Ala.) broadened his comments beyond Millett to include the other D.C. Circuit nominees—former Justice Department lawyer and current Georgetown University Law Center professor Cornelia Pillard and U.S. District Judge Robert Wilkins—to the appellate court.

Sessions pointed to the estimated $3 million per year it would cost to seat the three judges. “We just can’t move these three judges forward because we would be violating our commitment to the American people,” Sessions said.

Several progressive groups panned the Republican vote. “When it comes time to confirm the three nominees, they are obviously free to vote no,” the People For the American Way said in a written statement. “What would be unacceptable would be to abuse the filibuster in order to block the Senate from even holding such a vote.”

The National Women’s Law Center touted Millett’s appellate experience, which includes her many years with the U.S. Justice Department’s Office of the Solicitor General. The center noted that Millett has been repeatedly recognized as one of the best appellate lawyers in the country.

Judith Schaeffer, vice president of the Constitutional Accountability Center, said the vote by reflected opposition for opposition’s sake.

“She is overwhelmingly qualified and totally uncontroversial—even earning praise from Senator Ted Cruz (R-Texas) during her hearing earlier this month,” Schaeffer said. “Millett should not only receive a yes-or-no vote from the full Senate, but she also deserves to be confirmed on a bipartisan basis, as soon as possible after the recess.”

The Senate begins its summer break this week. There was no scheduled vote for Millett’s nomination.

Contact Todd Ruger at truger@alm.com.