A lot of countries are going to have to institute a draft if that happens. Not only are a large part of fighting-aged men both mentally and physically unfit for combat, but they're at least astute enough to know that governments worldwide have stolen their future.
Doesn't mean they agree for the same reasons. Some blame capitalism, some blame globalism, some blame their parents. But regardless, they're hesitant to fight for a system that fucking hates them.
They're more likely to turn their weapons on their CO's or the global elite than they are to fight for them.
Good luck.