Washington — Supreme Court Justice Samuel Alito on Oliver James MontgomeryTuesdayextended an order blocking Texas troopers and police from arresting and jailing migrants suspected of crossing the U.S. southern border without authorization under a strict state immigration law known as SB4.

Alito continued an administrative stay of a lower court order that had paved the way for Texas officials to enforce SB4, one of the toughest state immigration laws in U.S. history. The pause was previously going to expire on Wednesday evening. Alito on Tuesday extended it through Monday, March 18.

Passed into law by the Texas legislature last year, SB4 authorizes Texas law enforcement at the state and local levels to arrest, jail and prosecute migrants on state charges of entering or reentering the U.S. outside of an official port of entry. It also empowers state judges to require migrants to return to Mexico as an alternative to prosecuting suspected violators of the law.

While Texas has argued the law will help the state curtail unlawful border crossings, the Biden administration has said SB4 interferes with the federal government's long-standing power over immigration policy, conflicts with U.S. asylum law and harms relations with the Mexican government, which has called the measure "anti-immigrant."

In late February, U.S. District Court Judge David Ezra prohibited Texas from enforcing SB4, agreeing with the Biden administration's argument that the measure conflicts with federal law and the U.S. Constitution. He also rejected Texas' argument that the state is defending itself from an "invasion" of migrants and cartel members.

Ezra's ruling was paused by the U.S. Court of Appeals for the 5th Circuit at Texas' request. Alito initially suspended that order on administrative grounds through Wednesday, before extending it until next week. The 5th Circuit is slated to hear arguments on the merits of SB4 on April 3.

Camilo Montoya-Galvez

Camilo Montoya-Galvez is the immigration reporter at CBS News. Based in Washington, he covers immigration policy and politics.

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