Greenville, S.C. July 3, 2014. USA Today. By Rudolph Bell (Greenville News). Greenville has joined a movement of local governments installing plaques bearing the national motto, "In God We Trust."

In God We Trust America, a nonprofit organization that encourages local governments to display this motto, reports that 373 local governments in 15 states — most recently Mobile, Ala. and Greenville — have voted to display the motto. But the American Civil Liberties Union is questioning whether the religious phrase belongs in government buildings at all.

Greenville's County Council voted unanimously on June 17 to display the motto inside Council Chambers at County Square.

County Councilman Fred Payne said he proposed the idea after getting an email newsletter from In God We Trust America.

"We're just reaffirming this is a great nation, and it was made great by a great God," Payne said.

Executive director of the ACLU of South Carolina Victoria Middleton said it's not clear why the county would want to post a religious phrase that could make residents who practice a different religion, or no religion at all, uncomfortable.

"Especially in a courthouse or council chambers, people should not be made to feel like outsiders in their own community because they don't share the dominant religious view," Middleton said.

"In God We Trust" began appearing on U.S. coins during the Civil War and was made the national motto by Congress in 1956, according to the U.S. Treasury Department's website.

Jacquie Sullivan, who launched in God We Trust America around a decade ago, said that most Americans support the motto's display in public buildings.

"It's completely, solidly legal," Sullivan said.

Sullivan said her records show that Anderson became the first South Carolina county to vote to display the motto on June 7 and Greenville became the second when it approved the idea.

Greenville County Attorney Mark Tollison, asked if he'd reviewed the legality of displaying the motto, pointed to a legal opinion from former South Carolina Attorney General Charlie Condon.

Condon concluded in the 2002 opinion that displaying the motto does not violate the First Amendment prohibition on laws "respecting an establishment of religion."

He cited three federal appeals court rulings that upheld use of the motto against Establishment Clause challenges.