§ 12406. National Guard in Federal service: call

Whenever—

• (1) the United States, or any of the Commonwealths or possessions, is invaded or is in danger of invasion by a foreign nation;
• (2) there is a rebellion or danger of a rebellion against the authority of the Government of the United States; or
• (3) the President is unable with the regular forces to execute the laws of the United States;