That’s a very complex question, one with no simple answer, but a bare bones version is China. Japan invaded China in ‘37, and by 1941, the US government, which had a large and rather vocal Chinese lobby, had had enough. The US enacted trade embargoes on many materials declared to be related to the war in China, such as oil and steel. Trade would be reopened if certain goalposts on an American-backed plan for peace were met. Japan didn’t feel like it could back down, and the embargoes were hitting the import-reliant Japanese economy hard. Therefore, it was decided that Japan would attempt to seize the resource-rich European colonies in the Pacific. The Philippines were (erroneously in retrospect) seen as a dagger straight into the heart of the supply lines of a potential invasion of the Dutch East Indies, and the British holdings in the Pacific. Therefore, it was felt that the US must be quickly knocked out in order to achieve their ultimate goal of conquering China.
Japan underestimated the US military, overestimated their own forces, and completely misread the politics of the US. They were hoping that a swift series of military victories could bring the US to the negotiating table like Russia in 1906. They were very, very wrong.
Don’t forget Japan had invaded Manchuria in 1931 , had defeated Russia in the 1904 war, and had invaded Korea before that. Japanese militarists and emperor thought they could do no wrong. The oil embargo also didn’t stop Japan from the scrap with Russia in 1939-40. Japan was in an aggressive mood and needed to take out the U.S. and Britain to further her plans of Asian domination. They miscalculated.
Agree on all counts. The Japanese believed that they were racially superior (and btw, still do)to westerners and even their fellow Asians. Thereby, they held a deep resentment that white westerners were the colonial masters of large chunks of Asia which they considered their right to rule. Also, being that they (Japanese) did have aspirations to have hegemony over the Pacific and all the land associated with that region, including much of China they needed large quantities of natural resources such as iron and oil. When the U.S. embargoed them from access to these resources they had to look elsewhere, such as to SEA, Australia and China. However, they (Japanese) knew that inorder to conquer these countries and to rule the Pacific it would have to take out the U.S. Pacific fleet. Hence, the attack on Pearl Harbor and the following coordinated attacks on strategic countries along the Pacific rim. Btw, initially, the citizens of these various countries perceived the Japanese not as conquerors but as welcome hero's who had arrived to free them from the “white man's yoke”. Sadly, they soon learned that enslavement is enslavement regardless of the color of one’s master - and the Japanese were very harsh masters indeed...
Still can’t figure how dumb they were to attack the USA
NO way we would have attacked them for going into SE Asia
Hell the vast majority of the American public wanted no parts of war with Germany or Japan until Pearl harbor
Big blunder on their part