Because the President is the Commander-in-Chief of the Armed Forces of the United States, he possesses the power to federalize any National Guard unit and place it under his direct command. He could the order the National Guard unit to enforce his will, and any attempt to refuse his orders would be mutiny, punishable under the Uniform Code of Military Justice.
So this doesn’t apply?
State Active Duty (SAD)
The Governor can activate National Guard personnel to “State Active Duty” in response to natural or man-made disasters or Homeland Defense missions. SAD is based on State statue and policy as well as State funds. Soldiers and Airmen remain under the command and control of the Governor.