I wish I could believe that our ideals have been betrayed at Abu Graib and Guantanimo, but the US generally doesn't have a problem with coerced confessions and prisoner abuse: as far as I can tell, most Americans believe that if you're accused, you're guilty and if you're guilty, you deserve whatever is done to you. This was all in place before 9/11.
They don't mind police lying to accused people to get confessions. It's been a lot of work to get videotaping of even a few interrogations. Plea bargaining is standard practice, even though it's obviously pressure to get innocent people to plead guilty.
Convictions have been overturned by DNA evidence, but it's taken a lot of pressure from outside the government. And it can be a hard haul just to get the DNA tested-- if it hasn't been destroyed.
Defense attorneys are on the automatic hate list for a lot of people.
There is generally no concern for prisoner rights, or as it's commonly said "If you can't do the time, don't do the crime."
A lot of the best fighters against these abuses say that the real America is better than Abu Graib. That level of extreme abuse isn't typical, but opposition to that sort of thing wasn't principled and wasn't pervasive enough to even begin to keep it from happening.
I'm talking about the sort of gut-level opposition which meant that, as bad as Abu Graib was, mutilation wasn't a standard part of torture, even though the whole chain of command was free to do what it pleased. That's what a real taboo looks like. What we need is to get from that much (and it's something-- not all cultures, including ours in the past, have that taboo) to an equal revulsion against trying to get false confessions or taking out hatred on helpless people.
I'm not saying that our worst is the real America, but I don't think our best is, either. I'm taking the real America (to the extent that the concept is meaningful) to be our usual.
Maybe saying we aren't really like that is the best strategy, maybe the most likely way of making a change is by assuming it's already the underlying reality, but it just isn't true, and if it was ever true, please tell me. America is enough better than a lot of places that there's a steady flow of illegal immigrants, but that's not the same thing as taking the Bill of Rights seriously.
If we're to have an end to torture, it's going to be by the general public acquiring new and better visceral reactions.