A man urges people to vote against the Houston Equal Rights Ordinance outside an early voting center in Houston on Wednesday, Oct. 21, 2015. The contested ordinance is a broad measure that would consolidate existing bans on discrimination tied to race, sex, religion and other categories in employment, housing and public accommodations, and extend such protections to LGBT people. Photo: Pat Sullivan, AP

A man urges people to vote against the Houston Equal Rights Ordinance outside an early voting center in Houston on Wednesday, Oct. 21, 2015. The contested ordinance is a broad measure that would consolidate existing bans on discrimination tied to race, sex, religion and other categories in employment, housing and public accommodations, and extend such protections to LGBT people. Photo: Pat Sullivan, AP

HOUSTON — After a drawn-out showdown between Houston’s popular lesbian mayor and a coalition of conservative pastors, voters in the nation’s fourth-largest city will soon decide whether to establish nondiscrimination protections for gay and transgender people.

Nationwide, there’s interest in the Nov. 3 referendum: Confrontations over the same issue are flaring in many places, at the state and local level, now that nondiscrimination has replaced same-sex marriage as the No. 1 priority for the LGBT-rights movement.

“The vote in Houston will carry national significance,” said Sarah Warbelow, legal director of the Human Rights Campaign, a national LGBT-rights group. She noted that Houston, with 2.2 million residents, is more populous than 15 states.

The contested Houston Equal Rights Ordinance is a broad measure that would consolidate existing bans on discrimination tied to race, sex, religion and other categories in employment, housing and public accommodations, and extend such protections to gays, lesbians, bisexuals and transgender people.

The outcome is considered uncertain. Two recent polls commissioned by Houston TV stations showed supporters of the ordinance with a slight lead, but each poll indicated that about one-fifth of likely voters were undecided.

Opponents contend the ordinance would infringe on their religious beliefs against homosexuality. Copying a tactic used elsewhere, they also have labeled it the “bathroom ordinance,” alleging that it would open the door for sexual predators to go into women’s restrooms.

“Even registered sex offenders could follow women or young girls into the bathroom,” says an ad produced by Campaign for Houston, which opposes the ordinance.

The measure’s supporters denounce these assertions as scare tactics, arguing that such problems with public bathrooms have been virtually nonexistent in the 17 states that have banned discrimination based on gender identity.

Mayor Annise Parker, whose election in 2009 made Houston the largest U.S. city with an openly gay mayor, is among those expressing exasperation.

“The fact there is so much misinformation and not just misinformation, just out and out ludicrous lies, is very frustrating,” Parker recently told reporters. “I’m worried about the image of Houston around the world as a tolerant, welcoming place if this goes down.”

Parker has vented some of her frustration on Twitter in tweets criticizing former Houston Astros player Lance Berkman. In ads for Campaign for Houston, Berkman said the ordinance would “allow troubled men who claim to be women to enter women’s bathrooms, showers and locker rooms.”