air national guard of the united states units or members may be called up for federal active duty in times of congressionally sanctioned war or national emergency. the president may also call up members and units of the air national guard using a process called "federalization", with the consent of state governors or equivalents, to repel invasion, suppress rebellion, or execute federal laws if the united states or any of its states or territories are invaded or is in danger of invasion by a foreign nation, or if there is a rebellion or danger of a rebellion against the authority of the federal government, or if the president is unable to execute the laws of the united states with the regular armed forces.