Answer:There are a number of reasons. First of all, American businesses looked for new markets abroad, and so some kind of imperial policy was thought necessary to achieve this goal. European colonial powers such as Great Britain and France had pursued such a policy for many years with much success; and as the American economy was rapidly becoming the world's largest, there was a certain logic to the United States emulating their example.
With growing economic power went growing political and military power. The United States was now recognized as a major player in international politics, and imperialism was a natural outcome of this. European countries had enhanced their standing on the world stage by the acquisition, development, and exploitation of their colonies, and it was thought that the United States might also do this. No longer was it enough for the United States to see itself as a beacon of liberty or the land of opportunity; it must also be respected in the old-fashioned way: hope this helps.
One of many results of Japan's invasion of Korea in the 1500s was "gradual opening of Japanese culture to other influences," since this ended a period of relative Japanese isolation.
The Monroe Doctrine granted the United States the ability to independently intervene in the trading economy. Having the ability to act alone and be neutral to war situations allowed them to make economic decisions based off of what they felt was best for them to prosper.
