The U.S. Department of Justice has filed a motion in federal court arguing Metro violated the Archdiocese of Washington's religious freedom when the transit agency refused to sell the organization space for Christmas fundraising ads.
Attorney General Jeff Sessions said the Justice Department filed the legal brief to commemorate Religious Freedom Day, which President Donald Trump declared for Tuesday, Jan. 16.
Metro cited its ban on "issue-oriented advertising" when it rejected the ad.
DOJ argued their move violates the Constitution.
"As the Supreme Court has made clear, the First Amendment prohibits the government from discriminating against religious viewpoints," Associate Attorney General Rachel Brand said in a statement. "By rejecting the Archdiocese’s advertisement while allowing other Christmas advertisements, WMATA engaged in unconstitutional viewpoint discrimination."
The ad design showed shepherds and sheep, as in a classic Nativity scene, with the words "Find the Perfect Gift."
Metro spokeswoman Sherri Ly previously said rejecting the ad was in line with the agency's policies.
"In 2015, WMATA changed its advertising policy to prohibit issue-oriented advertising, including political, religious and advocacy advertising," she said in a statement. "The ad in question was declined because it is prohibited by WMATA’s current advertising guidelines."
Metro barred political and religious advertising after an activist group submitted a cartoon depiction of the Prophet Muhammad to run as an ad at Metrorail stations and on buses.
The same group hosted a contest to draw Muhammad in May 2015 in Texas. Two gunmen opened fire on an security officer there and then were killed.