A federal judge in San Antonio on Wednesday blocked Texas from enforcing its ban on so-called sanctuary cities, questioning the constitutionality of a law that has pitted Republican state leaders against several Democratic-leaning cities.

The judge’s ruling was only temporary, and prevents the law from taking effect on Friday while a suit against it goes forward. But the decision, which Texas said it would appeal, served as a legal blow to one of the toughest state-issued immigration laws in the country and puts the brakes on a measure backed by the Trump administration that critics had called anti-Latino. The law has become so divisive that it served as the backdrop of a shoving match at the Texas Capitol between Hispanic Democratic lawmakers and their white Republican colleagues.