A late tweak backed by some of the chamber's most conservative voices could ensure that law enforcement across the country's second-largest state can inquire if people are in the country illegally during traffic stops and other fairly common interactions - which opponents say will spark the kind of immigration crackdown that the Trump administration has so far been unsuccessful implementing nationally.
The key 93-54 vote advancing the bill came just before 3 a.m. and followed 15-plus hours of heated, sometimes tearful debate, much of it from outnumbered Democrats unable to stop the bill. Final approval that again broke along party lines helped the proposal clear the House in the late afternoon.
RELATED: Inside the debate on the "sanctuary cities" bill
It would allow Texas to withhold funding from county and local governments for acting as sanctuary cities. Other Republican-led states have pushed for similar policies, but Texas would be the first in which police chiefs and other officials could face a misdemeanor criminal charge of official misconduct and be removed from office for not helping enforce immigration law.
An entity failing to follow the law could be subjected to a civil penalty of $1,500 for a first offense and $25,500 for any subsequent violation.
"Sanctuary cities" has no legal definition, but the bill is needed to "keep the public safe and remove bad people from the street," its House sponsor, Rep. Charlie Geren, said.
"If you don't do something to get arrested, or hang out with someone who does, this bill isn't going to affect you," said Geren, a Fort Worth Republican.
The Texas House proposal originally allowed local law enforcement officers to inquire about federal immigration status only if someone is arrested. A version passed in March by the state Senate went further, permitting immigration questions for anyone detained. But a floor amendment backed by tea party lawmakers extended the House version to apply to those detained as well as those arrested and passed 81-64 - bringing the full bill closer to what the Senate previously approved.
Democrats, and even some veteran Republicans, unsuccessfully opposed the change. The American Civil Liberties Union of Texas said it would "promote racial profiling based on appearance, background and accent."
The state Senate's version is still different enough from the House's that the two chambers must compromise on a finished bill. Similar efforts have collapsed in the past, meaning the issue isn't yet fully settled.
RELATED: 'Sanctuary cities' bill comes into focus in Texas
President Donald Trump is trying to withhold federal funding for sanctuary cities, but a federal judge in California has issued a preliminary injunction preventing him from doing so. Texas, though, is moving forward regardless of what happens nationally.
Sally Hernandez, the sheriff of Travis County, which includes liberal Austin, enraged conservatives by refusing to honor federal requests to hold suspects for possible deportation if they weren't arrested for immigration offenses or serious crimes such as murder. But Hernandez softened her policy after Gov. Greg Abbott cut grant funding to the county and she has said she'll conform to the state's ban if it becomes law.
Hernandez praised House Democrats for spending hours speaking against the bill in a statement Thursday saying, "They recognized the cost of forcing local law enforcement to do the job of the federal government and the liability it places upon us."
Other sheriffs warn the bill could make their jobs harder if immigrants - including crime victims and witnesses - fear the police.
"Today we've made real that fear," said Roland Gutierrez, a San Antonio Democrat. Many of his colleagues decried what they called a "show me your papers law."
Wednesday night, dozens of protesters, many waving signs and banners skewering the bill and its supporters, gathered inside the Texas Capitol to chant pro-immigrant slogans in English and Spanish. Some protesters later filed into the House visitors' gallery to applaud bill opponents on the floor.
"God is watching what you're doing," one woman yelled at Republican lawmakers before being escorted out.
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