When it comes to primaries, Republicans usually place a high premium on party loyalty to endorsed candidates and that translates as less competition. But in the Pennsylvania Supreme Court race, it is the Democrats who will have less choice on May 19.

Three Republicans are seeking their party's nomination: Superior Court Judge Cheryl Lynn Allen and Superior Court Judge Joan Orie Melvin, both from Western Pennsylvania, and Philadelphia Common Pleas Judge Paul P. Panepinto.

The Democrats' sole candidate for nomination is Superior Court Judge Jack Panella from Easton.

The Supreme Court is the highest in the commonwealth and receives some 2,500 civil and criminal appeals every year. The court has not always lived up to the venerable reputation it should enjoy, however, as the oldest appellate court in the nation, dating to 1684.

Fortunately, the Republican candidates are first-rate -- all are highly recommended by the Pennsylvania Bar Association.

The state GOP committee's endorsed contender is Judge Melvin, 53, of Marshall. After attending the University of Notre Dame and receiving her law degree from Duquesne University, she practiced law for five years before being appointed a city magistrate in 1985. Two years later, she became chief magistrate and founded a domestic violence court.

She was appointed to Allegheny County Common Pleas Court in 1990 and was elected to a full term a year later. In 1997 she won election to Superior Court and was retained by the voters in 2007. As the state bar association said, she is fair-minded and has a solid record of performance.

An equally strong candidate, also from Allegheny County, is Judge Allen, 61, of Hampton. Her first career choice after graduating from Penn State University was education, and she became an elementary school teacher in the Pittsburgh Public Schools before receiving her law degree from the University of Pittsburgh.

That experience with young people later served Judge Allen well. She was an assistant solicitor in the Allegheny County law department and in private practice until 1990, when she was appointed to Common Pleas Court. She won a full term in 1991 and won retention in 2001, and she was assigned for 12 of those years to juvenile court, where she implemented programs to help children. She was elected to Superior Court in November 2007. Again, the bar association view echoes the local opinion -- this is a judge held in high esteem.

Being from Philadelphia, Judge Panepinto, 59, who attended Villanova and received his law degree from Widener, isn't well known here, but clearly he too has a record of achievement. He worked in the Philadelphia Family Court from 1971 to 1990, starting as a probation officer and becoming a juvenile master. He was appointed to Philadelphia Common Pleas Court in 1990, won a full term in 1991 and was retained by the voters in 2001. He now serves in the civil division but previously served with distinction as administrative judge of the family division.

If Judge Panepinto were to get the GOP voters' nod to face Judge Panella in the general election, only one woman would remain on the seven-member court (Justice Jane Cutler Greenspan is stepping down).

But the difficult choice in this race is selecting one amply qualified woman over another. Both judges would bring the necessary knowledge and experience, and a place on the Supreme Court bench would cap an excellent career. For Judge Allen, time is running out. Barring unforeseen circumstances, another opening won't occur for another six years when her age would be a negative for some voters (justices have a mandatory retirement age of 70). This is a consideration for us that divides her from the equally good Judge Melvin, who is young enough to run another day.

Although Judge Allen changed her registration from Democratic a few years ago on philosophical grounds, the Republicans have not returned the favor by endorsing her in a primary. They can make amends here and pick an eminently qualified African-American woman who has the potential in the fall to swing black Democrats to the GOP.

The Post-Gazette endorses Cheryl Lynn Allen for the Pennsylvania Supreme Court.