The military is a fairly Republican demographic, but that didn't keep the Democratic convention from making appeals to them.
Beyond the obvious, one line stood out to me:
Ane we aren't leaving anyone behind on the side of the road.
That's basic morality in the military, and the President brought it into a broader context. It's just the difference between the essence of the Democratic message and the essence of the Republican message. We take care of each other. We take care of our fellow Americans.