A recent YouGov survey showed 61% of Americans believe a WW is on the horizon. If the US is involved, 6% would volunteer for military service with an additional 9% if there was an imminent threat of invasion of US soil. Slightly higher at 26% for non combat/aid roles.
The corresponding numbers for Sweden are 44% willing serve in combat roles to defend their country. I always had the impression Americans in general are far more patriotic than Swedes. What gives for such low numbers in the US?