A proposal to strengthen a Louisiana's law against bestiality has received surprising pushback from Republicans, who claim it would open the door to ditching the state's (already unconstitutional) ban on gay sex.

The U.S. Supreme Court struck down sodomy laws nationwide in 2003 with Lawrence v. Texas But Louisiana is one of the few states that still has them on the books—in fact gay men have been arrested for having sex there as recently as 2015.

The state's existing "crime against nature" statute actually lumps anal sex and bestiality in the same category, "The unnatural carnal copulation by a human being with another of the same sex or opposite sex or with an animal." Democrats have introduced a bill to disentangle the two, but a handful of state Republicans claim that's just a "Trojan horse" to decriminalize gay sex. (Which, of course, already happened 15 years ago.)

"This bill was written because the far left wants to undermine our other laws that protect family and traditional values that the people of Louisiana hold dear," Sen. Ryan Gatti told AP. Gatti is one of the 10 senators who voted against SB 236.

"That was our concern," he added, "that it most likely will be used as a Trojan horse to delete the sodomy law."

Representatives from the Humane Society are dumbfounded—it's the first time they've seen any sort of backlash on an anti-bestiality proposal. "It’s quite surprising," said executive director Leighann Lassiter.

SB 236 has passed in the state Senate, though it faces an uncertain future in the House, where members of the conservative Louisiana Family Forum hold considerable clout. "I think the provisions of his bill go way too far," Forum president Gene Mills told AP.