Question about countires defenses?

Actually the airbombing is very spendy. Did you know that we are now using bombs that dont have explosives in them. They are just filled with concrete. But really I do think you could virtually cut a country off like the middle ages seige tactic. We own the oceans, and regular patrols to stop land transport would be pretty effective. I doubt we would have to bomb their infrastructure. I bet we would get tagged for inhumane on it though. Not like shock and awe was very humane either.