Pentagon tells governors National Guard must be vaccinated against COVID

• "To ensure that we maintain a healthy and ready military force capable of accomplishing our mission to defend this nation and to protect the American people, vaccination against COVID-19 is an essential military readiness requirement," the secretary added.

Driving the news: The letters were sent to the governors of Alaska, Texas, Wyoming, Mississippi, Iowa, Nebraska and Idaho. Alaska and Texas have taken joint legal action against the Pentagon's vaccine mandate.

• The lawsuit from Texas, joined by Alaska, argues that when National Guard units are serving the state, the federal government does not have authority over them.
• Austin's letters to these two states say that the secretary cannot comment in detail due to the ongoing litigation.

The big picture: Austin in August mandated that all service members, including the National Guard, be inoculated against the coronavirus.

• The mandate states that Air National Guard and Army National Guard members who fail to get inoculated will be barred from drills and other duties, and won't be paid even when they're under state control.