Utah Senator Mike Lee has reintroduced a controversial bill that seeks to protect opponents of same-sex marriage.

Twenty-one Republican senators, including Marco Rubio of Florida, Ted Cruz of Texas and Orrin Hatch of Utah., have co-sponsored the measure.

The First Amendment Defense Act (FADA) seeks to bar federal “discriminatory action” against people and corporations who oppose marriage equality based on a “religious belief or moral conviction.” The bill would also protect those who discriminate against people who engage in sex outside of marriage.

Lee and Idaho Rep. Raul Labrador, a Republican, first introduced FADA in 2015, but the bill stalled in the House and Senate.

The Human Rights Campaign (HRC), the nation's largest LGBT rights advocate, called FADA “harmful legislation that would legalize state-sanctioned discrimination and undermine key civil rights protections for LGBTQ people.”

“Supporters of this legislation are using religious liberty as a sword to hurt LGBTQ families rather than staying true to our long tradition of it serving as a shield to protect religious expression from government overreach,” David Stacey, government affairs director at HRC, said in a statement.

Lee told BuzzFeed News in November 2016 that he planned to reintroduce FADA. On the campaign trail, President Donald Trump pledged to sign the bill, saying it was needed to protect “the deeply held religious beliefs of Catholics and the beliefs of Americans of all faiths.”