Imperialism and World War One best served the interest of the United States in that it provided the country power, land and trade options.
The United States most clearly stated that it would get what it wants when the President established a League of Nations, which is similar to the modern-day United Nations (UN). Or during the age of Imperialism where we set the Great White fleet to Japan just to establish a military post, or where we forced Queen Liliuokalani to give up her rule in Hawaii, and the Open Door Policy that led to the Boxer Rebellion in China. The United States fought and threatened in order to establish its reputation as an ignorant, self absorbed country.
Also, the United States got more than its adequate share of land. Just from force it took Hawaii, the Philippines, and Cuba. The United States also got Portorico, and the Panama Canal which also increased trade rapidly.
In these new territories, the Platt Amendment was installed, which forced the territories to trade with and help the United States if it was at war. So if Cuba went to war with China, the United States would help, but in return if the United States went to war with France, Cuba and all the other territories would help.
Lastly the United States introduced new ways of trade. It installed the Platt Amendment, the Roosevelt Corollary, and China from the open door policy. Not only that, but through the Panama Canal the United States made easier routes to Asia and Australia. Without trade the United States would not be able to sell its products on a world wide scale, and get products that were not available there. Cars such as the BMW and the Voltswagon were both invented in Europe, and without trade,