OKLAHOMA CITY (AP) — Oklahoma’s Republican governor and the state attorney general are suing in federal court to exempt the state’s National Guard from a Biden administration COVID-19 vaccine mandate.

Gov. Kevin Stitt argued in a statement Thursday that the Biden administration’s Defense Department overstepped its constitutional authority by subjecting the National Guard to the mandate it imposed on the active duty military.

Stitt had exempted the Guard from mandatory vaccinations, but Defense Secretary Lloyd Austin rejected that exemption.

Stitt said that although National Guard members are paid by the federal government, he remains their commander in chief under federal and state constitutional and statutory law.