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 [begin] 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.

[Update: Well, that didn't last long:]

Alito’s last-minute order, the third time the high court stepped in to pause enforcement of the law known as Senate Bill 4, came around 4 p.m., when a previous order blocking SB 4 was to end.

The one-page order from Alito – who handles emergency petitions out of Texas, Louisiana and Mississippi – included no deadline, saying only that the delay in enforcing SB 4 had been extended “pending further order” of either Alito or the court.