Whenever used in this code, in specifying or defining the rights of employees of the State, or of any county, city and county, city, public district of any type or class, or other public or municipal corporation who are absent from their duties as such employees while in the active military service of the United States of America or of the State of California, or while assigned to duty with the military forces of the United States of America or of the State of California in the full time paid service of the American Red Cross, the word “war” shall mean: (a) whenever Congress has declared war and peace has not been formally restored; (b) whenever the United States is engaged in active military operations against any foreign power, whether or not war has been formally declared; or (c) whenever the United States is assisting the United Nations, in actions involving the use of armed force, to restore international peace and security.