Four reasons that the US switched from isolationism to imperialism were as follows economic, social, political and lastly religious motives.
Step-by-step explanation:
Economy was the main cause that lead to imperialism , Americans understood that new markets are required for the export purpose. Second cause was social and moral motives that is the Americans understood that western ideas should be circulated mainly they circulated ideas related to medicine, law as well as religion. Political was also important cause that lead to imperialism that competition took place so that new colonies can be formed.