OKLAHOMA CITY (AP) — The adjutant general of the Oklahoma National Guard is warning members that refusing to receive the coronavirus vaccine could end their military careers. Brig. Gen. Thomas Mancino says in an open letter that Oklahoma Army and Air Force members will eventually be subject to the U.S. Defense Department’s vaccination mandate. Defense Secretary Lloyd Austin has said National Guard members who refuse COVID-19 vaccination will be barred from federally funded drills and training required to maintain their Guard status. Austin has rejected a request by Republican Gov. Kevin Stitt to exempt Oklahoma members from the mandate. Stitt maintains he is the commander of the state Guard and the state is suing to overturn the vaccine requirement.