Answer:
The United States should be mostly isolationist, and in some cases and with a few exceptions, interventionist.
Step-by-step explanation:
The United States should be isolationist most of the time for several reasons. One reason is that military intervention in foreign countries is costly for the United States, and it is also costly for the countries that are intervened. Often, American intervention does not improve, or even worsens the social and political situation in those places.
Another reason is that the United States does not necessarily have the legitimacy or right to intervene in most domestic affairs of other countries.
However, as the most important superpower in the world, and the country with the largest and more powerful military by far, the U.S. should intervene in those cases where a humanitarian crisis is unfolding, for example, when a population is threatened with genocide. In these cases one can argue that the U.S. has a moral obligation to intervene, but only insofar as the goal is to prevent an humanitarian crisis from happening.