Petey, if you need help fighting a war on our behalf, you should ask for it.
A volunteer military would work, yes.
But your resources are finite. How much help would you provide?
And who would then protect you from the militaries of those who do not volunteer to help?
By drafting the most problematic aggressors first, I solve two problems at once.
You're turning Andromeda into a giant space-Australia.
Australia turned out okay, right?
Hah! I just realized how much you look like a koala.