Spread democracy--along with ideas of manifest destiny and "city upon a hill", the US believed they were the model for democracy. By becoming imperial powers they could train others to be democratic. Needed military and trade ports in the Pacific--with more trade occurring with China and Japan the US needed naval ports along the way to support US shipping. To also support the shipments, a strong navy was needed to protect the ships. Gain global power--European countries were proving to be a modern world power, a country needed to acquire colonies. US imperialism would allow the US to become a modern, industrial power.
