The Archdiocese of Seattle has defended a Catholic high school's decision to fire a gay vice principal who married.

Mark “Mr. Z” Zmuda lost his job as vice principal at Eastside Catholic High School in Sammamish, Washington on December 18 after school officials learned that Zmuda married his longtime partner over the summer.

Students rallied to Zmuda's side, launching a campaign calling for school administrators to reconsider their decision.

On Wednesday, supporters delivered a petition signed by more than 20,000 Christians.

“Please listen to the students at Eastside Catholic and reinstate their vice principal,” the petition reads. “If Pope Francis says he won't judge gays and lesbians, you shouldn't be firing them.”

Greg Magnoni, director of communications for the Archdiocese of Seattle, met with the crowd of supporters who had gathered to deliver the petition addressed to Archbishop J. Peter Sartain, who has previously expressed his opposition to marriage equality.

(Related: Bishop Peter Sartain claims gay marriage would harm society “beyond repair.”)

“Catholic schools have a right to expect that school leaders will not only pass on Catholic teaching, but model it for students,” Magnoni told the crowd. “Mr. Zmuda's decision presented the school with a difficult challenge; one that required a lot of reflection and prayer.”

In a written statement, Sartain defended the school's decision to terminate Zmuda.

“Catholic teaching in all its breadth is the hallmark of Catholic schools and we have a right and responsibility to help them uphold their principles and traditions,” Sartain said.

“Leaders of Catholic schools are charged with the responsibility of both imparting and modeling our teaching. The recent personnel decision by the board and administrators at Eastside Catholic regarding Mr. Zmuda was made after a great deal of prayer and consultation. In no way was their goal to be discriminatory to anyone but to be faithful to their mission as a Catholic school. The Archdiocese supports their decision. The decision has been misunderstood and mischaracterized by some, and we now have an opportunity to help our students learn even more about Catholic teaching.”