However, I would concur. The US has painted itself into a bad corner. There's no doubt Saddam Hussein was viciously evil, and his regime deserved to die. And there's no doubt that release brought on a lot of sectarian violence, much as the death of Tito did for Yugoslavia.
But it's not hard to say that the US buried their goodwill in unethical behaviour. It's hard to be saints, but Abu Ghraib was allowed to happen, via a culture that was directed by the ethics at the top. Similarly the knowingly false grounds for entering Iraq - WMD - which had only slim pretense of being sanctioned by the UN.
And, most jarring of all, continued financial support for Israel, without pushing them to settle with their neighbours.
Constructive ethics is harder. It's slower, and sometimes more costly upfront. But... a quote from Bill Clinton:
"Since we can't kill, jail or occupy all of our enemies ... we also have to spend some time and money making more and more partners and fewer enemies," he said. "It is so much cheaper to alleviate poverty, put kids in school, fight disease ... in a poor country than it is to fight a war."
Well, that's how you win a war. That's how you nation-build.
Of course, this is easy for anyone to say. The US political beast is a hard one to manage; it needs someone with vision. And ethics.