Let's say it was a nation like France (which was illrgally trading through oil for food), or China, or any one of a number of other nations... simply by outing that your looking at an international charlie foxtrot that has to be dealt with.
Interesting, but it couldn't have been France, simply because helping another country having its own bomb was unconcievable for any of the administrations that run France since De Gaulle. Plus, if it had been France, Germany or Russia for that matter, they would have shut the fuck up before the war hoping for the US to find and get rid of the nukes.
However, the country that made possible for Saddam Hussein to think at one point of becoming a nuclear power was France indeed, as it provided the nuclear civilian technology that was used in Iraq (But the chemical et biological weapons, which were the only WMD that Saddam at some point actually had, were taken elsewhere).
the military was overconfident after initial successes in Afghanistan
I suggest you take a look at Gen Shinseki hearings (They are probably on Youtube). The military wasn't nearly as overconfident as Rumsfeld and the political leaders were.
One thing seems funny, though, is how people tried to make a film to prove something that at least 3 major countries were saying before the war. Russia, Germany and France were against this war, and all they got for it was hatred ^^, whereas they were only thinking about the huge mess that a war in Iraq was going to be.
Another funny thing (which is going to be a lot less funny in a few years), is how Iraq seems to be paralysing the United States now, when it comes to react to a true nuclear build-up, this time in Iran.