We started it with Japan when we imposed an embargo and sanctions on Japan in 1937 after Japan's aggressions against our trading partner, China.
I would differ.
For years many historians have made that claim. In fact, that is what my dad, a WWII veteran, told me. Because, at the time it was the excuse given by our government and the press. However, in truth, refusing to trade with another nation is hardly a legitimate reason to go to the lethality and chaos of all-out war.
People die in all out wars.
And assets get destroyed.
The Japanese took out 75% of our Pacific fleet in one day. They lost 20 or so aircraft. All their ships sailed home Scott Free. Many months later our Mitchell bombers made a desperate suicide mission to merely poke them in the face.
Germany surpassed the USA in virtually every item and product of prosecuting a war. At the start, Japan and Germany had better, and more modern, weapons but lost to attrition and our ability to catch up in technology and sheer production mass.
At the end of the day, our advances in technology and sheer production of war material, leveled both countries, quite literally to dust.
Japan and Germany wanted our resources and manufacturing capacities. Essentials they lacked. Essentials we ramped up to beat them.
We didn't win because we were smarter or had better weapons and fighters. We won because we could out produce both Japan and Germany combined.