To nazshooter, I have mentioned useful duties of a real militia several times but even here on this board there doesn't seem to be much interest. However, it is an arguable point as to whether or not it would make the country less likely to engage in foreign adventures, as you put it.
One reason is that the current full integration of the national guard into the overall military picture, as I understand it, was supposed to insure the complete agreement of the citzenry in any major military undertaking. But so far it doesn't seem to bother anyone any more than having females among the casualties. I suspect that the reason is because so relatively few among us actually ever have anything to do with the armed forces anymore, or so I am led to believe. In my own family I served, my son served and my son-in-law is currently serving. I guess we're among the few.
Other countries have, at times, raised military used specifically for home defense. That is, they weren't supposed to be liable for overseas service, although really only a handful of countries ever had overseas colonies. We've had troops stationed overseas for over a hundred years but never in what you would call a colony, unless you count Hawaii.
It is also worth pointing out that required military service such as exists in most countries always meets a certain amount of resistance from those who actually have to go, even including Switzerland, but I suppose that's natural.
Shoot low, sheriff. They're riding Shetlands!
Underneath the starry flag, civilize 'em with a Krag,
and return us to our own beloved homes!
Buy War Bonds.