Tuesday, civil rights groups and Texas’ largest border county filed a lawsuit, calling the measure that Republican Gov. Greg Abbott had signed into law less than 24 hours earlier an unconstitutional reach over the U.S. government’s authority on immigration. The Texas law is due to take effect in March. The lawsuit, filed in federal court in Austin, was brought by El Paso County along with the American Civil Liberties Union and the Texas Civil Rights Project. It was filed against the head of the Texas Department of Public Safety, whose troopers could arrest migrants, and the El Paso County district attorney, whose office would potentially prosecute cases in that border community. The measure allows any Texas law enforcement officer to arrest people who are suspected of entering the country illegally. Once in custody, they could either agree to a Texas judge’s order to leave the U.S. or be prosecuted on misdemeanor charges of illegal entry. Migrants who don’t leave could face arrest again under more serious felony charges.