User blog comment:GrandMethuselah67/Lore-Sheet: The Technocratic Coalition of Humankind/@comment-4867780-20161104101038/@comment-26322734-20161104101719

The Coalition does have a military of self-healing automations that's supplied by the Technocracy and manufactured by Malcolm's Crown Industries so that citizens don't have to pay for it via taxation. Besides that, due to their massively free trade policies, many other civilizations would much rather trade with them than go against them (seriously, these people import and export basically any good or service), and many extraterrestrial corporate interests send private militaries to protect their shares of property in T.C.H. territory, followed by extaterrestrial governments offering military support in times of need via alliance contracts either signed by individual republics, the Technocracy, or corporate interests.

So all in all, it's a mix of the T.C.H's own military and a conglomeration of foreign militaries, making the Coalition actually one of the more secure places in the galaxy.