Those who ignore history, are doomed to repeat it.

George Santayana

War is abhorrent. However, history is replete with accounts of war. In fact, the mile stones of the history of mankind are marked by conflict, tribe against tribe, nation against nation. Empires have been built through armed conflict, since the beginning of humanity.

Either religious belief or territorial greed provokes most wars. Sometimes, one nation simply has what another nation wants, or presumes to need.

Usually, war is not spontaneous. As we analyze the national and international conflict, a chain of events leading up to the final conflict is evidenced. Such is the case with the attack on Pearl Harbor.

The following is the time line of the prelude to the act:

The attack on the military forces of the United States at Pearl Harbor, Territory of Hawaii did not just happen nor was it a quick reaction to initiatives instituted by President Roosevelt. The Japanese believed Roosevelt was pushing them into a corner and they were convinced that they must act to protect the Empire. Gordon Prange in "At Dawn We Slept" describes pre-attack events in detail. The description of these events note the mistakes made on each side.

• July 1937 - The Japanese Army invaded North China from Manchuria; eight years of combat with the Chinese began.
• December 1937 - The gunboat USS PANAY, while on routine duty in Chinese waters, was attacked by Japanese aircraft. It is not known if the attack was intentional or an accident but Roosevelt looked for ways to punish Japan. Nothing became of this incident because the Japanese government apologized, paid for all damages, and promised to protect American nationals.
• October 1938 - With the continued German military rearmament program and European leadership capitulation at the Munich conference, President Roosevelt asked Congress for $500 Million to increase America's defense forces. This was done because he believed that Germany was a threat to the United States. The Japanese saw this build up as a direct threat to their Empire because the United States was the only country in the Pacific, which could impede their expansion.
• February 1939 - Japan continues its conquest of China by occupying Hainan Island of the Southern coast. This occupation improved Japan's ability to interdict maritime trade routes. Because the U.S. was the primary military threat in the Pacific, Japan had prepared war plans to deal with this problem. The U.S. had similar war plans aimed at Japan. The Japanese plan was to conduct one large naval battle against the American Navy, destroying it, resulting in the inability of the U.S. to interfere with Japanese expansion throughout Asia.
• August 1939 - Admiral Isoroku Yamamoto assumed command of Japan's Combined Fleet. Having lived in America for several years he knew the type of people Americans were, thus he knew that this war plan was impractical. He needed a new plan, which would remove the threat of U.S. intervention from his flank.
• January 1940 - Some time between January and March 1940 Yamamoto devised his plan to destroy the United States' Navy in Hawaii and demoralize the American people. No actions were implemented to put the plan into effect.
• July 1940 - Trade sanctions followed by a trade embargo were imposed in an attempt to stop Japanese expansion, resulting in increased ill-will and additional political problems with Japan.
• January 1941 - Admiral Yamamoto begins communicating with other Japanese officers, asking them if an attack on Pearl Harbor would be possible. The final outcome of these discussions was that it was possible but would be difficult. Secrecy and surprise were the two elements that were most important to the success of this plan. However, one wonders how secure the flow of information was around the Imperial Naval Staff. Because on January 27, 1941, Joseph C. Grew, the U.S. Ambassador to Japan, wired Washington that he had learned information that Japan, in the event of trouble with the U.S., was planning a surprise attack on Pearl Harbor. No one in Washington could believe this. If someone had believed it, the attack on Pearl Harbor might possibly have been avoided.
  
  While many thought that war was possible, no one believed that the Japanese could surprise us. Most senior American military experts believed that the Japanese would attack Manila in the Philippine Islands because Manila's location threatened the sea-lanes of communications as the Japanese military forces moved south. Another possible location for an attack was believed to be toward the north into Russia because of the war in Europe between Germany and the Soviet Union.
• February 1941 - As the Japanese were conducting preliminary planning for the attack, Americans were preparing to defend American property. Admiral Husband E. Kimmel, Commander in Chief of the U.S. Fleet, and Lieutenant General Walter C. Short, Commanding General of the Hawaiian Department, prepared Hawaii for a possible attack. Defense of the islands was an Army responsibility though the Navy did play a major role in preparing to repel such an attack. Adm. Kimmel planned on taking his fleet out of the harbor and confronting the enemy at sea. With this in mind, both officers communicated with their seniors in Washington attempting to obtain additional men and equipment to insure a proper defense of all military installations on Oahu. At this time, war production of the U.S. was still limited resulting in the dispersal of materiel around the world trying to fill everyone's needs; Britain, Russia, the Philippines and Hawaii.
• March 1941 - Nagao Kita, Honolulu's new Consul General arrives on Oahu with Takeo Yoshikawa, a trained spy. As the military of both countries prepared for possible war, the planners needed information about the opponent. The U.S. knew that Hawaii was full of Japanese intelligence officers but because of our constitutional rights very little could be done. Untrained agents like Kohichi Seki, the Honolulu consulate's treasurer, traveled around the island freely noting all types of information about the movement of the fleet. When the attack occurred, the Japanese had a very clear picture of Pearl Harbor and where individual ships were moored.
• April 1941 - During this time period U.S. intelligence officers continued to monitor Japanese secret messages. American scientists had developed a machine, code-named 'Magic' which gave U.S. intelligence officers the ability to read Japanese secret message traffic. 'Magic' provided all types of high quality information but because of preconceived ideas in Washington some data was not followed up on and important pieces of the pre-attack puzzle were missed. Japanese consular traffic was also intercepted which provided additional intelligence.
  
  While the U. S. had all the data needed to arrive at a clear picture of Japanese intentions, the Navy had an internal struggle between the Office of Naval Intelligence and the War Plans Division about which department should be the primary collection office. When the War Plans Division was finally designated the first in line for data, all of the Navy's intelligence collection was degraded. To further complicate this problem, the Army had its own intelligence office, G-2. At times the Army and the Navy did not talk to each other, again reducing the ability to derive Japan's intentions. Finally, Washington did not communicate all the available information that was received to all commands, at times thinking that such a transmission would result in duplication. All in all, the U.S. knew that Japan was going to expand its war but the question remained, where? If U.S. Intelligence people had communicated, preparations for the attack could have been improved.
• May 1941 - Admiral Nomura informed his superiors that he had learned Americans were reading his message traffic. No one in Tokyo believed that their code could have been broken. The code was not changed. If the Japanese had changed their code, the surprise of the attack would have occurred as it did but would we have been as poorly prepared or could the result have been worse? This mistake would have impacted follow-on actions through 1942.
• July 1941 - Throughout the summer Yamamoto trained his forces. His staff and the Naval General Staff finalized the planning of the attack: what route to travel on, how much fuel would be required for the trip, what U.S. ships would be in the harbor and where they would be moored. The Japanese planners also had to coordinate their own requirement of additional military action around Indochina. Which action was more important and which would provide the greatest gain had to be worked out.
• November 1941 - Tokyo sends Saburo Kurusu, an experienced diplomat to Washington as a special envoy to assist Ambassador Admiral Kichisaburo Nomura, who continued to seek a diplomatic solution. Japan wanted the United States to agree to its southern expansion diplomatically but if they were unsuccessful, they would go to war. On the 16th, submarines, the first units involved in the attack, departed Japan. On the 26th, aircraft carriers and escorts, the main body of the attack force, began the transit to Hawaii.
• December 6 - President Roosevelt makes a final appeal to the Emperor of Japan for peace. There is no reply. Late this same day, the U.S. code-breaking service begins intercepting a fourteen-part message from the Japanese. After deciphering the first thirteen parts they are passed on to the President and Secretary of State. The Americans believe a Japanese attack is imminent, most likely somewhere in Southeast Asia.
• December 7 - Pearl Harbor is not on a state of high alert. Based on available intelligence senior commanders have concluded that there is no reason to believe an attack is imminent. Aircraft are therefore left parked wingtip to wingtip on airfields, anti-aircraft guns are unmanned with many ammunition boxes kept locked in accordance with peacetime regulations. There are also no torpedo nets protecting the fleet anchorage. And since it is Sunday morning, many officers and crewmen are leisurely ashore...

""There is no such thing as an inevitable war.
If war comes it will be from failure of human wisdom."
(Bonar Law - Speech before WW 1)