What best characterized American foreign policy since 1865?

What best characterized American foreign policy since 1865? Has it been imperialist, isolationist, or something distinct from either of these? Trace American foreign policy from the late nineteenth century through the end of the Cold War. What distinct periods best narrate policymakers’ shifting views regarding America’s proper place in the world? What drove the shifts between the key periods? Identify specific time periods that best characterize America’s policy. It is better to select a few periods and provide detailed analysis than to try and cover everything in this period with only generalizations.