Having foreign policy you disagree with does not make America non-democratic. There are many areas in which the American government doesn't seem to represent the will of the people, but military spending and interventionism are broadly popular.
Now, if you want to argue that people have been duped into holding beliefs contrary to their own best interests, I think you could make a strong argument. But that's not the same thing as saying that the government doesn't reflect the beliefs they DO hold.
The US is the place where the tail wags the dog. The wealthy minorities that are interested in war (for financial reasons or otherwise) put billions into pro-war public support. So it is difficult to say if this is something that the population really wants or if they're being duped into accepting.
Now, if you want to argue that people have been duped into holding beliefs contrary to their own best interests, I think you could make a strong argument. But that's not the same thing as saying that the government doesn't reflect the beliefs they DO hold.