A federal judge in Texas has largely halted an Obama administration initiative that grants work permits and protection from deportation to undocumented immigrants brought to the United States as children, though he allowed the more than 600,000 young people already in the program to keep their protected status.

U.S. District Judge Andrew S. Hanen, a Republican appointee, sided with Texas and other states in his ruling that President Barack Obama (D) overstepped his executive authority when he created the program in 2012.

Hanen’s ruling called Deferred Action for Childhood Arrivals, or DACA, an “illegally implemented program” and said “the public interest of the nation is always served by the cessation of a program that was created in violation of law and whose existence violates the law.”

He issued a permanent injunction vacating the memo that created DACA in 2012, and remanded the issue to the U.S. Department of Homeland Security for reconsideration.