July 4, 2008
There is never any one reason for anything. Just that some things are more significant that others, but often any one, including the chief one, could disappear and the weight of other causes and momentum would continue. There are Japanese internal affairs I don't pretend to understand, but both Japan and Germany had political assassinations leading up to war. For this reason, the period of the 1960's was a concern about the US.
Japan wanted to be the leading power in Asia (Greater East Asia Co Prosperity Sphere was the code name). Just like Germany wanted to be in charge of Europe. My reading of the central reasoning will follow in a moment.
I spent a year in Europe in the 60's, arriving with two questions and found my answers. Why did German twice in a lifetime try to take over Europe? and, How were they almost able to do it? Germany was the most advance country in Europe on many fronts, plus organized and disciplined. A weekend would find the French enjoying themselves on the streets, the Belge and Hollanders would be cleaning the streets, but the Germans would be building things. They tried to take all of Europe including Euro-Russia because they were able. (That former colony across the Atlantic saved Europe at least one of the two times, maybe both times.) Why did they try to rule Europe? Just because they were the most capably able to do so ! From my military history interests, I note that the war was fought honorably while they were winning. When we stuck our nose in, then various atrocities came about. Skipping the obvious Final Solution, lets use the example of submarine warfare. A German U-boat sank a ship and while giving aid (typically water and directions to the nearest land), they found massive number of survivors, Italian POWs. They sent out a clear language call for international aid. The members of the wolf pack were the first to respond. A USAF bomber attacked the rescue flotilla. Orders from Germany, no more aid to shipping.
Japan was the most advanced nation in Asia. They thought they should rule and set about to do it. They were in the process of conquering China, but, because Japan is a resource poor island, they needed oil and mineral imports -- from the touchy Americans and from Dutch East Indies (the Southern Resource Area was their name for it.) The Dutch and the British were occupied with some national interests in Europe. There was no need for slow negotiations, just take what was needed for national success and settle up later. The Axis were succeeding in Europe, so Japan joined the Tripartite Pact. This strained relations to near breaking point with the USA which was a resource provider to Japan of gasoline and scrap iron for the military, Joining the Axis made Japan a belligerent of our Allies, Go back several years, the US and most of the world looked favorably upon the advanced Japan being a guide to backwards China, -- until the Peking massacre of 300,000 people. World option towards Japan fell. The Pact with the Axis was too much.
In parallel, the US sided with England against Nazi, The USN was in combat in the Atlantic, code name, All Steps Short of War. One third of the US Pacific fleet was sent to the Atlantic were they fought the Germans by replacing the Royal Navy in the western half of the Atlantic. Code name "Neutrality Patrol". We attacked U-boats, radioed for English ships to come take German merchant ships we found. An American pilot flying an American plane given to England spotted the Bismarck. US battleships, an aircraft carrier, and merchant ships made up a convoy transporting 20,000 British troops, from Halifax for the Far East in November ; the USN turned back Dec 7. The Brit troops landed at Singapore while Japs shelled the US ships; the ships escaped, while the troops marched into prison camps. And on and on. For the US to have continued sending resources to Japan after they jointed the Axis Pact would have been to directly aid our enemy's war effort.
Shutting off American oil and iron emphasized the importance of Dutch East Indies to the Japanese. Now, you can, with a few moments thought, easily list the steps required. England held the fortress at Singapore, The US had the Philippines. These had to be neutralized before walking into Java, etc. The army would take British Malaya (launched from Vichy provided Indochina) by the back door -- Singapore was defended from the seaward side, the land approach was open. The rest of SE Asia was not militarized and they could walk through one country to the next without opposition. The Australian's were busy in North Africa. The British were engaged with their tussle in Europe But their Ally, the USA, had to be dealt with. The US presence in the Territory of the Philippine Islands had to be addressed with force, but they were weak and unprepared. The real concern was the obvious expectation of the USN to sail across the Pacific to defend the Philippine Islands.
Well, what to do? In the Russo-Japanese war of 30 years earlier, the Japanese had launched a surprise attack. Lets try it again ; this time to take out the US Pacific Fleet . Other interesting points to Japan : with the fall of France, FDR authorized a Two Ocean Navy of 210 new ships including 12 aircraft carriers and 7 battleships. The first of these would commission in early 1942. MacArthur was preparing for war to start in April. The Japanese Navy was stronger in the Pacific in 1941 than the combination of all other nations. The Japanese army and air force had four years of combat experience and weapons development in warfare in China. The Japanese Navy had ten battleships and ten aircraft carriers. We had in the Pacific eight battleships and three aircraft carriers, you get the idea. After Pearl Harbor, we had zero battleships in service in the Pacific. The goal of Pearl Harbor was not to war with the US, but to discourage the US from going to war with Japan.
The Japanese thought they could become the only Asian power and with the whole Pacific and Indian Oceans as buffers from retaliation. Their thinking was that after they got the Southern Resource Area and a ring of defensive positions, they would favorably consider a request by the world for peace. They would agree and get on with their real goal -- the conquest of China.
Subsequent events proved they were almost right. They defeated the US Battle Fleet, the US Asiatic fleet, the British Far East Fleet, and the Royal Dutch Navy ; attacked from Hawaii to India, from Alaska to Australia, without losing a ship larger than a submarine or auxiliary destroyer. But, politically, they expected the world, (read, isolationist USA ) to be reasonable and accept the new occupations by Japan, negotiate a peace because this was the only logical thing to do.
But Fletcher slowed them down, sank six of their carriers. Battleships turned out to be of little value, The Axis built ten new aircraft carriers during the war; the US alone built 119. Once mobilized, the USA was overwhelming. Contrast this with the call in Congress of a few years earlier, "Schools, not ships."
A conclusion repeated over and over on this WW2 web site is that war is a come-as-you-are party. No capital ship (carrier or battleship) authorized after Dec 7, 1941, was completed in time to see service in the war. What makes Admiral Fletcher's success most significant is that he did it with the remnants of a depression era fleet against a larger and battle trained enemy.