Imperialism in The United States

Imperialism is an economic policy that extends a country's power through military force by conquering and taking control of smaller countries.  I no longer think that the United States should be imperialist.  This is due to the fact that several countries nowadays are allied together.  If the United States were to attempt to be an imperialist power we would struggle severely because of the protection from allied countries. The United States does have the strongest military power, but against multiple countries we would be vastly overwhelmed by the immense power of combined teamwork of other countries.  "I preach to you…that our country calls not for the life of ease, but for the life of strenuous endeavors."