A Legal Showdown on the Border Between the U.S. and Texas: What to Know

The Biden administration is suing the State of Texas over a new state law that would empower state and local police officers to arrest migrants who cross from Mexico without authorization.

On Thursday, a federal court in Austin is hearing arguments over whether to halt the implementation of the law, which is set to go into effect on March 5.

The case has far-reaching implications for the future of immigration law and border enforcement and has been closely watched across the country. It comes amid fierce political fighting between the parties — and within them — over how to handle illegal immigration and follows the impeachment by House Republicans of the secretary of homeland security, and the failure of a bipartisan Senate deal to bolster security at the border.

Texas has said its law is necessary to deter migrants from crossing illegally, as has happened in record numbers over the past year. The Biden administration argues that the law conflicts with federal law and violates the U.S. Constitution, which gives the federal government authority over immigration matters.

The law passed by the Texas Legislature, known as Senate Bill 4, makes it a crime to cross into Texas from a foreign country anywhere other than a legal port of entry, usually the international bridges from Mexico.

Under the law, any migrant seen by the police wading across the Rio Grande could be arrested and charged in state court with a misdemeanor on the first offense. A second offense would be a felony. After being arrested, migrants could be ordered during the court process to return to Mexico or face prosecution if they don’t agree to go.