Arizona Gov. Jan Brewer has vetoed a bill allowing ranchers to kill endangered wolves in self-defense.
Senate Bill 1211 would have allowed livestock owners to kill a Mexican gray wolf if one was caught attacking livestock or a person.
Wildlife activists say the bill violated the federal Endangered Species Act.
A separate bill approved by both chambers sets up a reimbursement fund for ranchers who lose cattle to wolves. It still requires final action.
Proponents say the federal government is overstepping its boundaries with its wolf-recovery program in Arizona and New Mexico.
Brewer vetoed the bill on Tuesday.