AUSTIN – Texas Gov. Greg Abbott once again inserted himself into a religion-related First Amendment dispute Friday, announcing his office had urged Attorney General Ken Paxton to issue an opinion in favor of law enforcement officers seeking to display crosses on their patrol cars.

"The U.S. Supreme Court has long recognized the demographic and historical reality that Americans 'are a religious people whose institutions presuppose a Supreme Being,'" Abbott's office wrote to Paxton, who has been asked to weigh in on the controversy playing out in sparsely-populated Brewster County. The office added that "the Court has never held that public officials are barred from acknowledging our religious heritage."

Multiple legal experts questioned that argument by the former Texas Supreme Court justice, saying that many courts have ruled specifically that the display of crosses on government property is a violation of First Amendment language prohibiting the government from establishing a religion.

The move marked the furthest that Abbott has gone in a months-long quest by Texas Republicans to ensure Christianity is not impinged upon in the aftermath of the Supreme Court's legalization of same-sex marriage last summer.

The promise to fight for "religious liberty" has become a rallying cry for the GOP, appearing in legislative orders ahead of next year's session and taking a prominent role in the presidential campaign stump speech of U.S. Sen. Ted Cruz.

Most recently, Abbott and others successfully lobbied Paxton to issue an opinion endorsing the display of "In God We Trust" on patrol cars. The plea issued Friday is step further because "In God We Trust" is a longtime national motto, while crosses have been associated almost exclusively with Christianity.

An Abbott spokesman acknowledged that the cross has a "special significance to Christianity," but he said it also has "historical significance."

"From the crosses at the American Cemetery in Normandy and Arlington National Cemetery, to the military medals and decorations this country bestows on its heroes, the cross is a symbol of service above self," spokesman John Wittman said.

Asked whether Abbott would fight for the right of law enforcement officers to display symbols with "special significance" to Islam or Judaism, Wittman said only, "Governor Abbott has never backed down from defending religious liberties, and he will always fight to protect the freedoms guaranteed in the Constitution."

The cross dispute arose last December after the Wisconsin-based Freedom From Religion Foundation complained that Brewster County Sheriff's deputies had put thin blue crosses on their cars. Rod Ponton, a district attorney for Brewster and three other West Texas counties, asked for an opinion from Paxton.

On Friday, a foundation lawyer said Abbott's position was based on "false history" and that the crosses were "a clear endorsement of Christianity over all other religions."

Experts said there were no political downsides to the move by the Republican in a conservative state.

"An overwhelming majority of Texas Republicans, as well as about half of Texas independents, believe Christians are discriminated against because of their faith," Rice University political scientist Mark Jones said. "By supporting the Brewster County sheriff's decision to allow officers to display crosses on their police cars, Abbott is signaling to these Republicans and independents that he's firmly on their side."

Cal Jillson, a political scientist at Southern Methodist University, agreed that the politics were "straightforward." Still, he said, there could be long-term consequences to what he described as "choosing exclusion."

Legal experts in Texas and elsewhere said that the crosses on patrol cars likely would be found unconstitutional in court.

"The Supreme Court has never upheld a display a cross as a sort of generic display of heroism or respect for God. It just hasn't happened," said Ira "Chip" Lupu, a George Washington University law professor who studies the separation of church and state. "I mean, come on. You and I know that crosses are specific to Christianity."

Lupu said the comparison to crosses at cemeteries is misleading because those symbols are on individual gravestones, signaling they are individual expressions, whereas symbols on government vehicles indicate a government position.

The high court's decision to allow the 10 Commandments to be displayed outside the Texas Capitol also is different because it was in a large area with other monuments and had been there for decades, said Charles "Rocky" Rhodes of the South Texas College of Law.

Rhodes added he was not surprised to hear of Abbott's position given the recent tenor of Texas politics.

"This is a hot-button political issue, and you definitely see Gov. Abbott and Attorney General Paxton, especially, trying to cast themselves as defenders of Christian freedom," he said.

Paxton is expected to issue a ruling within weeks.