The American Principles Project (APP) is urging Senate Republicans to oppose the so-called “Respect for Marriage Act” (RFMA) if senators fail to adopt strong protections for religious liberty.

Senators will gather on Tuesday to decide whether to adopt religious liberty amendments proposed by Sen. Mike Lee (R-UT), Sen. James Lankford (R-OK), and Sen. Marco Rubio (R-FL), and ultimately engage in a final vote on the bill. The Tuesday votes come after the Senate convened on Monday and voted 61-35 to end debate on a bipartisan amendment to the same-sex marriage bill that purports to protect religious liberty — although faith advocates say that amendment does nothing to shield Americans who have a traditional view of marriage from being targeted under the law.

The 12 GOP Senators who initially voted with Democrats to advance the legislation on November 16 once again sided with Democrats.

“We’ve seen this movie before. Democrats and their leftist allies propose a policy change which they claim is merely to protect some people’s rights but won’t affect most Americans,” APP President Terry Schilling  said in a statement on Tuesday. “A few Republicans go along in good faith, taking left-wingers at their word. But as a result, society is radically upended, with many Americans blindsided by the changes.”

Schilling continued:

Today, we stand on the verge of another such instance. H.R. 8404 claims to respect the religious liberty of Americans who hold to traditional marriage, but if it were to pass as it stands, nothing in the bill would protect those Americans from facing severe penalties for their beliefs. At the very least, an amendment such as that offered by Senator Mike Lee is required to minimally safeguard the rights of Americans of faith.

We strongly urge GOP senators to push for inclusion of the Lee Amendment in the final legislation. And if those protections are not included, for the sake of their religious constituents, Republicans must vote down the bill.

Sen. Mike Lee, whose efforts have arguably received the most attention, said his amendment “would ensure that federal bureaucrats do not take discriminatory actions against individuals, organizations, nonprofits, and other entities based on their sincerely held religious beliefs or moral convictions about marriage by prohibiting the denial or revocation of tax exempt status, licenses, contracts, benefits, etc.”

“Unfortunately, the current language of the RFMA does not strike that balance. Instead, it elevates the rights of one group at the expense of another,” Lee wrote in a recent op-ed. “The religious protections in my amendment offer the best path toward achieving the civility necessary for a pluralistic society to thrive. Therefore, I’m hopeful that my friends and colleagues can come together, united by a shared commitment to tolerance and mutual respect, to support my amendment.”