Both the U.S. Army and the U.S. Marine Corps argue that will to fight is the single most important factor in war. Will to fight helps determine whether a military unit stays in the fight and also how well it fights.

In On War, Clausewitz sees all wars as the sum of decisions, actions, and reactions in an uncertain and dangerous context, and also as a socio-political phenomenon. He also stressed the complex nature of war, which encompasses both the socio-political and the operational and stresses the primacy of state policy.

Clausewitz argues that war is a phe- nomenon consisting of three central elements or dominant tendencies. This triad, or trinity, is a paradoxical relationship “composed of primordial violence, hatred, and enmity . . .

• Battle of Gettysburg, 1863. Belligerents: Union vs Confederacy.
• The Battle of Cannae, 216 BC. Belligerents: Carthage vs Rome.
• The first day of the Somme, 1 July 1916. Belligerents: Britain vs Germany.
• The Battle of Leipzig, 1813. Belligerents: France vs Austria, Prussia and Russia.
• The Battle of Stalingrad, 1942-1943.

The Most Important Battles of World War II

• Battle of the Philippine Sea: June 1944.
• Battle of Berlin: April—May 1945.
• Battle of Kursk: July—August 1943.
• Battle of Moscow: October 1941—January 1942.
• D-Day: June 1944.
• Battle of Midway: June 1942.
• Battle of Stalingrad: August 1942—February 1943.

Soviet Union

The Battle of Stalingrad

World War II (1939-1945) was the largest armed conflict in human history. Although the war began with Nazi Germany’s attack on Poland in September 1939, the United States did not enter the war until after the Japanese bombed the American fleet in Pearl Harbor, Hawaii, on December 7, 1941.

Without the American entry into World War II, it’s possible Japan would have consolidated its position of supremacy in East Asia and that the war in Europe could have dragged on for far longer than it did.

Isolationists believed that World War II was ultimately a dispute between foreign nations and that the United States had no good reason to get involved. The best policy, they claimed, was for the United States to build up its own defenses and avoid antagonizing either side.