the 1941 bombing of Pearl Harbor by the Japanese was one of the most devastating attacks on American soil but just a few decades earlier Japan in the United States were allies in World War one so how did things get so bad between them it all comes down to oil to explain we need to go all the way back to the 19th century once an isolated nation Japan underwent a makeover of sorts to compete with the West known as the Meiji Restoration it embraced industrialization built up its military and restored Japan's Emperor as the powerful head of state aided by two successful Wars Japan aggressively expanded its empire the Japanese were becoming an imperial superpower until the Great Depression hit you see Japan is an island nation with few natural resources so it depends on international trade to keep its economy afloat the economic crisis put a stop to all that Japan was in a bind so it's military leaders who called the shots at this point decided the best defense against financial ruin would be a good offense they would invade nearby China particularly Manchuria for its plentiful resources like iron soybeans and land lots and lots of unsettled land so what does this all have to do with the United States well the US was a long-standing Chinese Ally and it watched uneasily from the sidelines as the two nations clashed in the 1930s but America wanted nothing to do with another war so it just denounced Japan's aggression tensions rose in 1937 when Japan invaded the Chinese city of Nanjing in doing so they attacked an American gunboat killing three and wounding dozens disturbing images coming out of war-torn China further swayed American opinion against Japan in response America attacked Japan's resources they imposed economic sanctions of aircraft scrap metal and other items crucial to Japan's military the u. s. hoped the sanctions would stop Japanese expansion but Japan doubled down invading French Indochina in 1940 and then team with Germany and Italy why those two countries because like Japan they were controlled by militaristic governments obsessed with conquest and driven by a deep sense of nationalism the final straw came in July of 1941 when President Franklin D Roosevelt announced a trade embargo on oil an oil shortage was an absolute disaster for Japan who relied on imports for ninety percent of its supply not only would this destroyed the Japanese economy but it would put its military at a literal standstill which meant no more expansion Japan resented the u.
s. for meddling in its quest to dominate Asia the only solution left for the Japanese was total war crushed the u. s.