When you have to draft chunks of your population in order to conduct warfare, public opinion is very much against you if your cause is not 'just'.
"If a nation cannot get enough paid volunteers to fight a war, that war is simply not worth fighting."
The flaw here is that there are always going to be people available to fight for a chance at gold. Additionally, and even more troubling for the United States, we are increasingly reliant on machines to do this work for us--there is increasingly no meaningful connection between the citizenry and the hawkish body politic.
If we do not have drafts, nor the possibility of drafts, then we find ourselves in a position where either:
1. We do not fight, for war is not worth fighting.
2. We continue to fight, and find ways of reducing the human requirement even further than it is already.
(2) is much more likely, given the history of man and the way our tech is evolving.
At best, this implies that one day we'll have robots blowing up other robots, all made by autonomous factories--this is merely a farcical misallocation of resources.
At anything less than best, this implies that we'll have robots blowing up lots of civilians or other troops. It doesn't matter whether the lives lost are ours or not, it matters only that things are worse off.
I'd suggest that the United States solely use draftees, and that we pursue national policies that don't require us to deploy widely to hostile areas.
