[jka]

That may be reasonable; I think it's important to consider how any party's involvement will be remembered as well, though. What groups will be glorified? Will that affect the way that those groups behave, what they feel proud about, and how they are treated in future?

There are a lot of roles required in successfully defending against an invasion -- maintenance, transport, heavy lifting, fighting, cooking; to name a few. Effective task assignment can be a resilience multiplier in the moment and also has a long-term echo.