Texas Attorney General Ken Paxton has filed suit seeking to force Illinois authorities to assist with returning nearly three dozen Democrats who fled to block a vote on a GOP redistricting plan.

The attorney general is calling on the “full faith and credit” clause of the U.S. Constitution, which says states should typically honor each other’s judicial proceedings.

Texas Republican U.S. Sen. John Cornyn said Thursday the FBI has granted his request to assist Texas law enforcement in locating House Democrats who fled the state, setting up a potential confrontation with Illinois Democratic officials who have vowed to protect them.