Which was not a challenge faced by America during the start of WWI?

There were many challenges the biggest being a push toward isolationism, a small military, and varying immigrant groups.

The challenges of being an isolationist country meant the US was ill prepared for war. Many Americans did not want to be involved and those that did could not agree on which side. A new wave of immigrants made it difficult for the US to pick a side during WWI.

A. establishing boarders with Canada and Mexico