A new bill introduced Thursday would forbid the federal government from withholding funds from groups that engage in voluntary religious activity.
The measure is called the Freedom to Pray Act.
Sen. Mary Landrieu, D-La., said she began working on the legislation after she heard the Young Marines program in Bossier Parish, La., could lose its federal money because there was voluntary prayer and the mention of God.
According to the Young Marines of the Marine Corps League website, members must agree to "keep myself clean in mind by attending the church of my faith" and to pledge that "I shall never do anything that would bring disgrace or dishonor upon my God, my Country and its flag, my parents, myself or the Young Marines."
Opponents view the requirement as a violation of the First Amendment's guarantee of freedom of religion.
"I think that Landrieu's Freedom to Pray bill is unnecessary, in that voluntary prayer is always allowed," Marjorie Esman, executive director of the American Civil Liberties Union's Louisiana office, said.
"The problem with this Young Marine program is they are required to swear to God - some god - and to attend church - some church - which requires them to have one and have a faith. Which is where the problem lies, and Sen. Landrieu's bill will not solve this problem," Esman said.
"While it's close to the line I think it's an important line," the Louisiana senator noted. "This is not promoting a specific religion. This is a voluntary program."
"People don't have to go to this program," she said. "We want to make clear that while it's important not to promote a specific religion, it's equally important not to push it away."