I could be wrong, but I always interpreted that scene as Michael telling Kay how senators and presidents can have their enemies killed just a like a Mafia Don. I don't believe Michael was talking about sending men off to war fighting America's enemies. I believe he is referring to senators and presidents killing off their personal/political enemies
You probably are right that Michael believed that senators and presidents have their enemies killed. I think he may have broadened it to mean sending men to war to make it plain to Kay
Do senators and presidents have their enemies killed?
Whilst some Presidents have been killed, the killings were not by their enemies?
What could Michael have meant? another debatable topic!
Kay: Senators and presidents don't have men killed...
Michael: Oh -- who's being naïve, Kay?
