Japan, isolated from the rest of the world for much of its history, embarked on a period of aggressive expansion near the turn of the 20th century. Two successful wars, against China in 1894-95 and the Russo-Japanese War in 1904-05, fueled these ambitions
The Japanese were conquest-mad ***holes. That's why.
Two sea battles (Coral Sea, Midway) destroyed all of their large carriers, and they didn't start to launch replacements until 1944. Loss of the former Dutch East Indies meant they didn't have sufficient fuel to keep their navy running, and the Pacific Ocean covers about half the Earth's surface. They had no reason to attack the US, and plenty of reasons NOT to.
Well, thats not true either.
We had already sent the American Volunteer Group to Burma before Pearl Harbor and they were not so stupid as to not be cognizant that the flying tigers were the tip of the spear in American Plans to force Japan out of China.
The end of their Empire was coming either way.
Pearl Harbor slowed it down.
“The Japanese were conquest-mad ***holes. That’s why.”
BINGO. Pretty simple, isn’t it? Stupid soyboy leftwing historians always point out that we were “embargo meanies” but that wouldn’t stop the japs due to a power hungry emperor..