Someone posed this question to askphilosophers.com.
You can read the philosopher’s response here. I thought the reply was interesting and I’m still pondering over it. Basically, the philosopher replied saying that military drafts in democracies should be considered mandatory. The reasoning is because if they are mandatory, then the people involved in the wars will definitely want to fight them (and will fight them) if they take the war to be just. If they feel the war isn’t just, then the people in the military will fight back. Vietnam is a good example of this. But if the military is purely voluntary, then they can’t complain because they volunteered to be in the military, whereas the people who find wars unjust can’t really fight the system because they’re not within the system to fight against the injustice itself. So instead, the people who find the war unjust can do nothing but sit idly by and watch. But over time, the people become more apathetic and don’t really care about the justice or injustices of wars.