Now take away the risk to American life and lower the cost of the attack significantly, and viola, you've got a much itchier trigger finger now. If you've played MW3, which would you rather do, use the drone to take out enemies or risk your character dying?
A drone totally changes the dynamics of the fight. If we were able to get tons of drones and "mechwarriors", I don't think wars would be quite as difficult to justify. As technologists we are often blinded by the coolness of things. As someone who has worked on AI for drones early on in my career (for the US govt), I shudder to think that I may have contributed in some ways to a terrible technology for humanity. At the time, I had friends deployed and in my head, I thought that it's better we have UAVs than my friends coming home in bodybags...