AUSTIN — The newest take on a Texas bathroom bill is so broadly written that some cities worry it would strip anti-discrimination protections not only from transgender people but also veterans, the elderly and pregnant women.

Under the proposal, introduced by House Republicans as a less restrictive option compared with the Senate's bathroom bill, cities would be forbidden from enacting bathroom regulations that protect the rights of people who are not already covered under federal civil rights laws, including members of the military.

The modified measure was intended to draw support from Texas businesses that are concerned about the bill's potential hit to the economy. But at least one constitutional scholar says the fix may create more problems.

The bill would allow cities to pass discriminatory laws banning certain people from using the restrooms of their choice, a factor experts said will invite legal challenges.

At best it’s problematic and at worst it's unconstitutional, said Dale Carpenter, a professor of constitutional law at Southern Methodist University’s Dedman School of Law.

“It’s a one-sided proposition in that it forbids a city from protecting someone from discrimination but it doesn’t forbid a city from discriminating against a person," Carpenter said. “It is very rare, if not unprecedented, to see actual language in a statute prohibiting classes of persons from being protected from discrimination."

"It would be kind of a constitutional lightning rod to put language like this into a statute."

Rep. Ron Simmons, the Carrollton Republican sponsoring the bill, said it "has been vetted with leading constitutional experts."

"I filed The Texas Protection Act (TPA) and believe it provides much needed privacy protections for Texans," Simmons told The Dallas Morning News in a written statement, referring to House Bill 2899. "The TPA affirms that Texas continues to be open for business while at the same time protecting Texans all across our great state."

Unlike the Senate bill, Simmons' proposal does not require people to use the bathroom that matches the sex on their birth certificate. But opponents say it is still meant to target the LGBT community, and transgender Texans in particular, even though it excludes terms like "biological sex" or "gender identity."

Supporters say passing a bathroom bill will protect women and children by keeping men out of the ladies' room. Business groups so far have sided with the opponents, but with six weeks left in the 2017 legislative session, there's still plenty of time to debate the issue.

What would the bill forbid?

Simmons' bill will get its first public debate in the State Affairs Committee on Wednesday. An amended version of the legislation that his office provided The News shows that the bill stands to undo decades of hard-fought protections for LGBT people and others by rolling all Texas cities back to federal minimum standards in the Civil Rights Act of 1964.

Federal law outlaws discrimination based on race, religion and national origin in places of “public accommodation," such as hotels, restaurants and movie theaters, and the facilities in them, like water fountains and bathrooms. Many states have broadened these protections to include other “protected classes” of people by banning discrimination based on other factors like age, marital status and sexual orientation.

Not Texas.

Simmons' bill would forbid cities, counties and school districts from passing regulations affecting bathroom use for any class of people who aren’t already protected in state or federal law. This means any city that’s extended its public accommodations laws beyond race, religion or national origin would not be able to enforce these rules when it comes to bathrooms.

Fort Worth and Austin have both added “age” as a protected class. If the House bill passes, neither city would be able to defend an elderly person who claims they were denied access to a shower or other intimate facility because of their age.

“We’re a very welcoming and open city and, yes, we want to be able to protect the rights of all our citizens,” said Austin City Hall spokesman David Green. “We’re in opposition to the bill.”

San Antonio added veterans as a protected class three years ago, the same time they extended their anti-discrimination laws to the LGBT community. City officials said they would be unable to enforce those protections if the bill becomes law.

“It does undo portions of our protections in this community,” said Jeff Coyle, director of government relations for the city. “We’re opposed.”

Carpenter said cities that have passed local laws protecting other groups in public spaces, like married people, families with children and pregnant women, would also be affected.

“This is broader than just the issue of just transgender access,” Carpenter said. “It goes beyond sexual orientation and gender identity to include things like veteran status and marital status and familial status.”

What does the bill allow?

While the bill would ax civil rights protections for a number of groups, LGBT rights advocates say the real danger is that it overtly targets transgender people.

The bill would nullify local laws in cities like Dallas that protect the right of transgender men and women to use the bathroom that matches their gender identity. It also would allow cities and schools to discriminate against the same people — or anyone else not protected under federal law — by barring them from using the bathroom they want.

“The result of this proposal would be an unprecedented form of exclusion from protections,” said Chuck Smith, executive director of the LGBT rights group Equality Texas. “It would take away existing protections, it would prohibit protections from being put in place in the future, and third, it would specifically allow discrimination to be enacted.

"It's wholly unacceptable."

The House bill will not be debated in a vacuum. It's going to be compared to the bathroom bill approved by the Senate last month, as well as a law recently passed in North Carolina. While some have compared Simmons' bill to the North Carolina law, that measure bars cities from passing any bathroom regulations and does not give cities the right to pass discriminatory laws.

The Senate's bathroom bill differs from the House proposal in that it would specifically prohibit people from using bathrooms in public schools, colleges and government agencies that don’t match the biological sex on their birth certificate. The measure was panned by business interests, who said it targeted transgender people and hurt the state’s chances of attracting interest from companies with young and diverse workforces.

House leaders echoed these concerns, raising the hopes of LGBT advocates who oppose the measure. Then on Thursday, House Bill 2899 was unveiled.

Simmons and State Affairs Committee Chair Byron Cook, R-Corsicana, said the bill is a more balanced approach they hope business groups could get behind. But the Texas Association of Business withheld their support last week, saying they'd continue "to focus on stopping discriminatory legislation."

Rebecca Robertson, an attorney with the ACLU of Texas, said the House bill is no better than the Senate's. By excluding phrases like "gender identity" or "biological sex," it nixes protections for a broad range of groups while still targeting the LGBT community, she said.

“It doesn’t single out transgender people by name but that’s obviously what it’s intended,” she said. “The idea that this is some sort of compromise is pretty upsetting.”

Robertson said the most concerning provision for her is that the House proposal, like the Senate’s, will mean school districts that have begun allowing transgender students to use the bathrooms they want will have to reverse course. Attorney General Ken Paxton, who has helped lead the charge against expanding LGBT rights in Texas, would be in charge of enforcing the law.

“This attorney general has argued that Title IX should not protect transgender kids,” Robertson said, referring to the federal law that prohibits sex discrimination in schools. “I would not say that this attorney general is going to be shy about forcing cities or school districts to stop protecting people.”