For Lou Weaver, the fight to keep the Houston Equal Rights Ordinance on the books is personal.

Weaver, a 45-year-old transgender man, has spent the last year working on the campaign supporting the city’s ordinance intended to protect lesbian, gay, bisexual and transgender people and several other classes from discrimination.

“This is my life. This is my reality,” said Weaver, a transgender community organizer. “I’ve never experienced discrimination in a job or in housing because I’m trans, but that’s a very different reality than a lot of my friends experience. I want to know that I’m going to be safe in the future.”

After months of heated campaigning, voters in the nation’s fourth-largest city are set to have the final word on the embattled nondiscrimination ordinance next Tuesday. In many ways, the vote is also the first referendum on the Texas gay rights movement since the U.S. Supreme Court legalized same-sex marriage in June.

First passed by the Houston City Council in May 2014 after intense public debate, the ordinance, better known as HERO, makes it illegal to discriminate against someone based on 15 different “protected characteristics,” including sex, race, marital status, religion and pregnancy. But it’s the sexual orientation and gender identity classifications that have become flashpoints for opponents.

The ordinance took effect for about three months. Almost immediately, conservative activists and pastors began collecting signatures on petitions calling for a referendum or repeal. When city officials later ruled that they hadn’t collected enough signatures, the opponents sued.

In July, the Texas Supreme Court settled the argument, telling the city council it had to consider a valid referendum petition and ordering the council to repeal the ordinance or put it up for public vote. 

The mayoral race was supposed to dominate Houston’s political sphere this fall, but the HERO referendum has stolen some of the spotlight. Both sides have poured millions of dollars into their campaigns, ads have filled Houston’s television and radio airwaves and political heavyweights have weighed in.

The ordinance is on the ballot as Proposition 1 and would apply to discrimination in housing, public accommodations, city contracts, public and private employment and to businesses that serve the public.

Led by Houston Mayor Annise Parker, ordinance proponents say it’s a local remedy to fight discrimination and would bring Houston — the biggest city in Texas — in line with dozens of states and major cities with similar measures in place.

Opponents argue the ordinance imposes on business owners’ religious liberties and duplicates federal law.

But for all that is at stake, the debate has largely been reduced to bathroom talk. Opponents argue that the gender identity protections would allow sexual predators to go into women’s bathrooms.

“This allows biological males, including registered sex offenders, to go into female restrooms, locker rooms and shower rooms all under the protection of law,” said Jared Woodfill, co-chair of the Campaign for Houston, which opposes the measure. “We think that’s dangerous public policy, and our position from day one has been we’re not willing to sacrifice the safety of our wives, our daughters and our mothers at the altar of political correctness.”

Ordinance supporters call that fear mongering. Parker, whose 2009 election made her the first openly gay mayor of a major U.S. city, said the ordinance’s language includes “best practices” from more than 200 cities across the country where public bathroom sexual predation hasn’t become an issue.

“They want to try to target a misunderstood group of folks and pound away and incite fears,” Parker said of bathroom arguments. She added that repealing the ordinance would be detrimental to Houston’s reputation as “a warm welcoming place that tolerates differences and respects diversity.”

At the start of early voting last week, Republican Lt. Gov. Dan Patrick blasted the ordinance and bankrolled a series of ads asking Houston residents to vote against it. Meanwhile, Julián Castro, the U.S. Secretary of Housing and Urban Development, lent his approval of the ordinance to the Houston Unites campaign, which is pushing for voters to affirm it.

With early voting set to wrap up on Friday, the ordinance’s fate remains uncertain. But most political observers agree that whoever wins, the margin of victory could be razor thin.

Recent polls by Houston TV stations have found that HERO’s supporters have a slight lead, but almost one–fifth of voters remain undecided.

Bob Stein, a Rice University political scientist who has been crunching early voting numbers, said turnout has been particularly high in African-American and white conservative precincts that would seem inclined to oppose the ordinance.

The increase in black voters is likely due to the mayoral candidacy of longtime state Rep. Sylvester Turner, who holds ground with a reliable African-American base, Stein said, but the “Republican boxes are strongly against HERO.”  

“I’m inclined to think what was a close victory for the HERO people might become a defeat,” Stein said.

While supporters remain confident voters will affirm the ordinance, losing the vote could be a major blow to Texas gay rights activists who say that nondiscrimination ordinances are the next frontier in their battle for LGBT people.

Texas is one of 28 states without statewide laws prohibiting discrimination based on sexual orientation or gender identity, and the Republican-controlled Legislature will almost certainly not enact any.

That leaves gay rights advocates pushing for nondiscrimination measures at the local level, but those efforts have resulted in a patchwork of protections across the state.

Including the Houston council’s 2014 vote on HERO, nine Texas cities with a population of more than 100,000 have passed nondiscrimination rules or legislation.

For at least a decade, Fort Worth, Dallas and Austin have had ordinances offering LGBT residents some degree of protection against discrimination in employment, housing and other public areas like buses and restaurants. San Antonio and Plano joined that list in 2014.

Despite the monthslong sparring, supporters and opponents of the nondiscrimination ordinance agree that the results of the election could have national implications.

“Do I believe the eyes of the nation are on Houston, Texas, right now? Absolutely,” said Woodfill, adding that the referendum has already made it into the presidential election and could push forward similar campaigns in other areas of the country.

For ordinance supporters, a loss could hand opponents the momentum to “turn back equality” or hold it back in other cities and states.

“If they can win here and overturn an ordinance, what does that mean for the rest of Texas?” Weaver said. “Would they go systematically across and try to take away what San Antonio has accomplished? What Fort Worth, Plano, El Paso have accomplished? Would they move across the South?”

Disclosure: Rice University was a corporate sponsor of The Texas Tribune in 2013. A complete list of Tribune donors and sponsors can be viewed here.