In late January, weeks before Kansas’ and Arizona’s odious anti-gay segregation bills drew fury across the country, the Mississippi state Senate quietly passed its own viciously homophobic “religious liberty” measure to virtually no fanfare. The bill, which is nearly identical to Arizona’s, would have the same effect as its now-notorious counterparts, allowing any private business to turn away gays at the door. But unlike Kansas’ and Arizona’s bills, which drew fierce Democratic opposition, the Mississippi measure passed with unanimous bipartisan support.

Yes, you read that right: Every single voting member of the state Senate, Republican and Democrat, supported a bill that would effectively allow segregation of gay and straight people throughout Mississippi. (Four state senators didn’t vote, but not for stated political purposes.) At the time, the bill drew no national attention and minimal local coverage. But now, in the shadow of the Arizona debacle, some legislators are starting to back away from their votes—and their excuses don’t quite line up.

The most vocal Democratic apologist for the bill, Sen. David Blount, defended his vote by claiming that he had no idea what he was supporting. “I learned that the bill passed unanimously by the state Senate a month ago to change the state seal also includes language that could legalize discrimination,” Blount stated. This seems highly implausible: The bill does contain an amendment adding “In God We Trust” to the state seal, but it’s a minor, one-page provision tacked on to the end of two and a half pages protecting a religious right to discriminate. Blount’s second claim is even more improbable:

I was not aware (nor was any other Senator or interest group or citizen that I have talked to aware) of this intention or possible result when we voted on the bill on Jan. 31. I am opposed to discrimination of any kind, including discrimination based on sexual orientation. Obviously, I should have (all of us should have) been aware of this.

A video of the debate reveals that senators spent about 12 minutes discussing the bill, never once bringing up the topic of homosexuality. One senator expresses his concern about individuals “praying facing Mecca”; another worries about religious liberty for “devil worshipping” and “voodoo.” One particularly lively legislator, who introduced himself as a “foot-stomping, back-slapping Baptist,” seemed earnestly confused about the bill’s purpose. Yet no senator seemed concerned about the measure’s implications for gay rights.* Perhaps some Democrats truly didn’t understand its horrific consequences for gay people; perhaps some did but are now trying to back away from their mistake following nationwide political fallout. Neither explanation is particularly comforting: Either legislators were shockingly negligent in the performance of their basic duty—reading the bills they vote on—or they were cruel enough to vote for a terrible bill and now too cowardly to stand by it.

Even if more senators like Blount apologize, moreover, they may have already opened Pandora’s box. The bill now sits in the House Judiciary B Committee, whose chair, Republican Rep. Andy Gipson, once publicly invoked a Bible passage supporting the death penalty for gays. (When questioned, Gipson elaborated that homosexuality is “unnatural behavior which results in disease” and “confusing behavior which is harmful to children.”) If the bill makes it past the strongly Republican-majority state House of Representatives, it will land on the desk of Republican Gov. Phil Bryant, who once denied spousal benefits to gay National Guard spouses in violation of a federal order.

After the surprising deaths of Kansas’ and Arizona’s anti-gay bills, there’s still some hope that politically savvy Republicans could let the Mississippi bill die. The fact remains, however, that the measure’s fate is currently in the hands of extreme homophobes with a long track record of zealous bigotry. If Mississippi becomes the first state in the country to legalize anti-gay segregation, Republicans will be remembered as the party elevating the bill into law—but Democrats will have the disgraceful distinction of having helped to hoist the abominable measure past its first major hurdle.

*Correction, Feb. 27, 2014: An earlier version of this post incorrectly stated that Mississippi maintains no records of legislative floor debate.