Which action indicated that the united states wanted to return to a policy of isolationism during the 1930s?

The action that indicated that the United States wanted to return to a policy of isolationism during the 1930s would be: Congress passed five neutrality laws. 
The neutrality laws basically prohibit all entities in the United States to export various arms and ammunitions to foreign countries that currently are at war. This will guarantee United States' neutrality in that war.

It was a combination of conquests and alliances