What role did the united states play after japan's invasion of manchuria?

This is a very broad question

Explanation:

The United States, along with other countries, criticized Japanese aggression but shied away from any economic or military punishments. Relations between the U.S. and Japan worsened further when Japanese forces took aim at Indochina with the goal of capturing oil-rich areas of the East Indies. Responding to this threat, the United States placed an embargo on scrap metal, oil and aviation fuel heading to Japan and froze Japanese assets in the U.S. Furthermore, the U.S. demanded that the Japanese withdraw from conquered areas of China and Indochina. Japan, sensing conflict was inevitable, began planning for an attack on Peal Harbor by April, 1941. The alliance systems of Japan, Germany and Italy were put into action by this time, but Russo-Japanese relations were cordial.

b) race riots in several cities

disease was the number one killer of native peoples. they had had little exposure to the diseases of europe. this led to some villages being almost completely wiped out and some tribes destroyed.