WASHINGTON – The Supreme Court refused Monday to hear the Catholic Church's challenge to a local ban on religious advertising.

The case, brought by the Archdiocese of Washington against the District of Columbia region's mass transit system, would have been the latest example of religious freedom appeals heard by the conservative-leaning court.

The justices already are considering four major religion cases, all brought to them by religious organizations after lower court losses:

• School choice: Three Montana women challenged a Montana ban on state funds being used to pay for religious education.

• Employment discrimination: Two Catholic schools in California claim the right to fire teachers under a "ministerial exception" to job discrimination laws.

• Birth control: The Trump administration wants employers and universities with religious or moral objections to be able to deny women insurance coverage for contraceptives, as required by the Affordable Care Act.

• Foster care: Catholic agencies providing foster care in Philadelphia want the right to turn down gay and lesbian couples based on religious convictions.

The new case stemmed from the archdiocese's effort in 2017 to place ads on buses and subway trains depicting the silhouette of three shepherds and sheep with the message "Find the Perfect Gift." The ads directed viewers to Mass schedules while encouraging service projects and charitable giving.

The Christmas-themed ads bumped up against the Washington Metropolitan Area Transit Authority's policy of banning religious, political and issue-oriented messages, enacted after complaints about an anti-Islam ad.

The Catholic Church wasn't alone in its challenge. Other groups fighting the policy ranged from the American Civil Liberties Union to People for the Ethical Treatment of Animals. A federal district court and the U.S. Court of Appeals for the District of Columbia Circuit sided with the transit system.

"Were the Archdiocese to prevail, WMATA (and other transit systems) would have to accept all types of advertisements to maintain viewpoint neutrality, including ads criticizing and disparaging religion and religious tenets or practices," Judge Judith Rogers wrote.

Associate Justice Brett Kavanaugh was on the circuit court panel that heard the case in 2018 but stood down once he was nominated to the high court. He recused himself from the case, which left only eight justices willing to participate.

For that reason, even conservative Justices Clarence Thomas and Neil Gorsuch agreed not to hear it. But they left no doubt about their opinions.

"The First Amendment requires governments to protect religious viewpoints, not single them out for silencing," Gorsuch wrote.

Former U.S. Solicitor General Paul Clement, representing the archdiocese, told the justices in legal papers that the circuit court's ruling conflicted with a more recent one from the U.S. Court of Appeals for the 3rd Circuit, based in Philadelphia.

"If Amazon or Macy’s had wanted to run an advertisement with the same text and graphics or with reindeer instead of shepherds, there is no question that WMATA would have readily accepted the advertisement," Clement wrote.

Donald Verrilli, another former U.S. solicitor general representing the transit system, responded that the advertising restrictions followed a series of community objections to political, religious and advocacy ads that led to vandalism and "heightened risks of terrorism."

Requiring WMATA to accept the archdiocese's ad, Verrilli wrote, would "wreak havoc with the sound administration of transit advertising programs, effectively forcing transit authorities either to accept all advertising or forego advertising revenue altogether."