During World War II the battle doctrine for the U.S. Navy was to dominate all the world seas at once while striking into the enemy heartland. This remained the main doctrine during 49 years of Cold War should it became a hot war with the Soviet Union. With the end of the Cold War, the doctrine needed to change as the position and type of enemy changed,. Now the Navy would fight mostly in the littoral regions near coasts (where 80% of the world's population lives); rather than over vast areas in the major oceans. The main force if the carrier battle group that as a weapons system is formidable in the projection of power and in actual striking power. The aircraft carriers planes and the battle group's cruise missiles can strike targets up to a 1,000 miles away. The carrier battle group remains America's force behind global power projection and diplomacy.