Answer:
Japan's imperialism was a problem to Western countries interests in Asia and it ended up with the participation of United States and Great Bretain into the World War II.
Step-by-step explanation:
Japan's imperialism was a problem to Western countries interests in Asia as they did not gained control from a part of continental China since their military actions started on Wolrd War I, but also attacked islands an other territories which were controlled by Western counestries such as French Indochina and British Malaya. This is is Why Western countries declared war on Japan as main effect of Japan's hostile actions. They want to put an end to World War II in the Pacific which end up with invasions to take back the territory and later with the first atomic bombing in human history, a total defeat for Japan.