Answer:
In my opinion it would not affect United States were not interfering in the internal problems of European forces.
Since Monroe's doctrine, strengthened by Roosevelt Corollary, their focused was on different areas, and assassination of archduke was nothing something that would provoke American public.
Step-by-step explanation:
There were also other crisis between European forces, including Balkan Wars, Moroccan crisis and many others and US didn't interfere.
Therefore, there is no reason for them to interfere, up until the moment when the States are provoked by someone.