Whenever any part of the National Guard of the State of Nebraska is in active federal service, whenever the President of the United States shall declare a national emergency, or whenever the Governor shall declare an emergency, the Governor is hereby authorized to organize and maintain within this state during such periods, under such regulations as the Secretaries of the Army and Air Force of the United States may prescribe for the organization, standards of training, instruction, and discipline, such military forces as the Governor may deem necessary to defend this state. Such forces shall be composed of officers commissioned or assigned by the Governor, and such able-bodied citizens of the state as shall volunteer for service therein, supplemented, if necessary, by men of the reserve militia enrolled by draft or otherwise as provided by law. Such forces shall be additional to and distinct from the National Guard and shall be known as the Nebraska State Guard. Such forces shall be uniformed.