Texas' SB4 immigration law takes effect after Supreme Court doesn't act, allowing state to detain migrants

A new Texas law known as SB4 that gives state officials permission to detain and jail migrants suspected of crossing the U.S. southern border without authorization took effect Monday after the Supreme Court declined to act.

The justices did not address an emergency request from the Justice Department to pause the law before 5 p.m. ET, when an earlier administrative stay expired. The move means Texas can being enforcing the controversial law, one of Gov. Greg Abbott's signature immigration policies, although the court could still issue an order pausing it as a legal challenge plays out.

Passed by the Texas legislature last year, SB4 criminalizes unauthorized migration at the state level, making the act of entering the U.S. outside of a port of entry — already a federal offense — into a state crime. It also creates a felony charge for illegal reentry at the state level.