I'd add to the people replying to this comment, about US citizens' responsibility, they have more responsibility than the average North Korean citizen, but not much. From what I understand, challenging the status quo in the USA is pretty difficult!
People who have power over the actions taken are responsible, pretty much the person itself and also the higher chain of command for the said person who commits whatever act to be held responsible for.
1. Those elected officials are not elected by everyone - in the case of GWB's first term (which many probably think of in this military context) it wasn't even a majority that elected him.
2. Those that do elect officials have a very small choice (lets say 2-3 people who could practically be elected). Further, I'd argue that most only vote on a few key issues, while the elected official has dominion over a vast number of issues.
I don't hold citizens as not at all responsible, but I think its at least fair to argue (in the above context) that the elected officials bear more responsibility - and blame - than the everyday citizen.
I would also disagree with politicians controlling the military -- perhaps the people in charge do have political power too, but I would argue that the political power and power over the military are rather indirect, it's not the same entity controlling the two, there are multiple people and entities with indirect relationships.
I am not responsible for an act you do with the knife I sold you last week, unless I did it in consent of you commiting the act. My parents aren't responsible for the acts I do.
Only when there's power, there's responsibility. Taxpayer does not have power over military, hence why taxpayer has no responsibility.
I do agree though, and this is why I've been a vegetarian for 10 years now.