Please be more specific. Resubmit the question with a time-period or a relevant event to consider.
On 2 August 1964, North Vietnam attacked two US Destroyers in the Gulf of Tonkin. Congress authorized President Johnson to react militarily
Japan had little in the way of natural resources and felt it need to expand militarily, rather than by trade, to get them. America opposed Japan's expansion, particularly its aggression against China.
they droped nuclear bombs on japan
The United States was involved militarily in World War 2 from 12-7-41 to 9-2-45 when the Japanese surrendered. They continued the aerial bombing of Japan until the surrender.
The US is involved in Latin America militarily because of the Monroe doctrine.
We declared war on Japan the next day. It led to the involuntary internment of Japanese-Americans out of fear of them maintaining loyalties to Japan.
Japan was defeated militarily by the might of the United States (plus two Atom Bombs).
Japan has never had a Fascist ruler or government. Japan was militarily aligned with Fascist Germany and Italy during WW2 as a part of the AXIS alliance.
They joined WW2 and bombed japan to make them surrender
Japan badly needed the oil and scrap iron, it was coming from the US. Should these resources be cut off? Japan would have to find them elsewhere. Japan viewed the possibility of Economic sanctions as a threat to its long-term objectives.
Since the end of the Second World War, the relationship between the United States and Japan has evolved to become exceptionally strong. Today, the two countries cooperate very closely militarily, technologically and in terms of trade. Statistics regarding the volume of US exports of trade goods to Japan from 1985 to 2011 show the strength of the relationship between the two countries.
They surrendered.