The Governor can activate National Guard personnel to "State Active Duty" in response to natural or human-made disasters or Homeland Defense missions. State Active Duty is based on State statute and policy and on State funds. Soldiers and Airmen remain under the command and control of the Governor.

the President may call into Federal service members and units of the National Guard of any State in such numbers as he considers necessary to repel the invasion, suppress the rebellion, or execute those laws.

But, unlike most of the other military forces, it can also serve a domestic law enforcement role. Additionally, the president can deploy the guard to serve missions overseas, as has been done in Afghanistan and the Horn of Africa.