Mary Beck Briscoe, currently the longest-serving judge on the federal appellate court based in Denver, will retire effective March 15.

Her announcement opens a second vacancy on the U.S. Court of Appeals for the 10th Circuit less than one month into the Biden administration. One week ago, Judge Carlos F. Lucero, who, like Briscoe, was confirmed to the bench in 1995 as a nominee of President Bill Clinton, also stepped down.

Both judges have assumed senior status, which is a form of retirement that still permits them to continue handling cases while opening one of the 12 active seats for a president to fill. Before the two retirements, seven of the judges were nominees of Democratic presidents and five were Republican nominees. That balance will not change.

The 10th Circuit hears federal appeals from the states of Colorado, Kansas, Utah, Wyoming, New Mexico and Oklahoma. Briscoe served on the Kansas Court of Appeals immediately prior to her appointment, and was the chief judge of the 10th Circuit between 2010 and 2015.

“I assume that the White House will consult with the Kansas senators and attempt to agree on a nominee who is well qualified and mainstream and acceptable to Biden and the senators,” said Carl Tobias, an expert on judicial selection at the University of Richmond School of Law. He added that it is rare for judicial seats to change states, and Briscoe’s spot on the bench will likely stay with Kansas, just as Lucero’s will be for an attorney in his home state of Colorado.

Briscoe, 73, attended the University of Kansas law school, graduating in 1973. She was the first woman to serve on Kansas’s state appellate court.

“She graduated at a time when there was only grudging acceptance of women in the major law firm[s] and courts. She was a true pioneer, and her professional achievements have opened doors for lots of others,” said Martin Dickinson, former dean of the KU School of Law.

In an interview for the Historical Society of the 10th Judicial Circuit, Briscoe said her most memorable case as a federal judge was the 2012 decision in Essex, et al. v. Kobach, in which the Kansas legislature failed to reapportion legislative districts following the 2010 census.

“The feud primarily pitted GOP moderates against their more conservative GOP colleagues,” noted the opinion. Briscoe was one of three judges on the panel that deemed the old districts violated the U.S. and Kansas constitutions, and approved a slate of court-drawn maps.