If we take this seriously, doesn't it come down to something close to "might makes right"? In other words, if a country can't defend itself it doesn't deserve to exist.
But “might makes reality” is quite accurate - if a country cannot defend itself it will indeed cease to exist.
Whether or not some external force attacks it or not is orthogonal to that.
I take your argument seriously. To a large extent it's simply a fact that a country populated by people willing to die on its behalf will outlast a country whose citizens lack that quality.
My point is that that's not a moral observation. It has nothing to do with "deserve". We can imagine a pacifistic country focused on art and technology that is conquered by a country of brutal philistine knuckle-draggers focused on war. Does the latter country "deserve" to conquer the former?