A federal judge in Austin on Thursday blocked Texas state officials from implementing a sweeping immigration law that would have allowed them to arrest, jail and prosecute migrants who cross into the U.S. illegally. The Justice Department and the American Civil Liberties Union had challenged the law known as SB4, which was set to take effect on Tuesday, March 5. In a 114-page order, Judge David Ezra of the U.S. District Court for the Western District of Texas granted the challengers’ request for a preliminary injunction preventing Texas officials from enforcing the state law. Ezra wrote that the Constitution and Supreme Court precedent make clear that states cannot enforce immigration measures without federal approval, and that the Texas law conflicts with federal law. In a statement, Texas Gov. Greg Abbott vowed to “immediately appeal this decision, and we will not back down in our fight to protect our state — and our nation — from President Biden’s border crisis.” Attorney General Ken Paxton soon filed notice with the court that the state was appealing the ruling.