Backers of an effort to put LGBT protections to a vote in Michigan announced Friday that they are calling it quits for 2016.

The bipartisan campaign committee Fair Michigan had won regulatory approval to begin collecting signatures to put a constitutional amendment before voters that sought to ban discrimination on the basis of sexual orientation, gender identity and sex.

Equality Michigan and the American Civil Liberties Union (ACLU) were outspoken in their opposition to the approach. The groups said they feared defeat at the polls.

Detroit attorney Dana Nessel co-chairs Fair Michigan.

“2016 presented a real, unique opportunity to give Michigan voters the chance at long last to update and expand our Constitution to prevent discrimination and ensure everyone is treated fairly after too many years of legislative inaction,” Nessel said in a statement. “We had the right language at the right time, backed by detailed research that demonstrated Michiganders of all political affiliations, backgrounds and communities across the state would have been behind this effort. Unfortunately, politics got in the way and created barriers to long-term success.”

The ACLU told The Detroit News that it will continue to lobby lawmakers to approve such protections.