* The 9th Circuit Court of Appeals permanently barred California from enforcing a state law that required federal immigration agents to display identification while on duty.

* The Justice Department sued to block the ID requirement alongside a related attempt to ban masks for federal agents and local police last fall.

* More than a dozen other states have pursued similar statutes, but the appellate court found that California’s law is invalid because it attempts to regulate the actions of federal authorities without authorization from Congress.