Japan invaded Manchuria in 1931. Although the other countries of the League of Nations disapproved of the invasion, there was no effective way to force the Japanese to desist. So, as no international body had the authority to intervene, the US did not interfere or challenge Japan's invasion.
Ten years later, in 1941, after Japan had taken Korea and most of China, the US announced an embargo on Japan's supply of oil. This led the Japanese to attack the US as a prelude to their conquest of the western Pacific.
A unofficial group of American pilots did fly to China beginning in 1937, under American veteran Claire Chennault.
(see the related link to "Flying Tigers" below)
novanet---- the unites states did not approve of japan's invasion but they did not interfere
JAPAN
Japan's incursion into Manchuria, the US embargo of oil to Japan and the attack by Japan on the US Fleet at Pearl Harbor.
The US imposed an oil embargo on Japan on August 1st, 1941 to motivate Japan comply with the US demands for Japan to leave Manchuria and stop the imperialism and murders.
Yes the Japanese only had Manchuria, Korea, and SE Asia at the time.
Manchuria
NO. The US and Japan have been at peace since 1945. Japan actually hosts a number of US military bases and the US is the key defense force protecting Japan from possible foreign invasions.
Japan invaded Manchuria in 1931 as a part of a larger strategy of territorial expansion, mostly for its resources. The US and Japan would not be engaged in World War 2 for another 10 years.
Since Japan has no oil, it needs to buy it from the US. In 1931 Japan invaded Manchuria. It upset the US and we felt the Japanese gaining military power. This was dangerous to the US, but Japan couldn't do anything without oil. So the US stopped selling oil to Japan in early 1941.
I answer this question with another question. Why is the category US in WW2?
Japan's inursion in Manchuria, the US Embargo on Japan, the German Invasion of Poland, the Japanese attack on Pearl Harbor and Hitler's decleration of war against the US.
It was the opening volley in the Pacific side of WWII. It was condemned by the League of Nations and the US.