I think the point of the article is that media demogogues have been suggesting strategies that are against the Geneva convention not that the US itself has yet broken this agreement. If it did, without going into the justification for it then technically Bush and his advisors could have to stand trial for war crimes, since war crimes are defined by this Geneva convention. This is not a problem as the US has refused to recognize the world court but if they did visit a country that did they would technically be subject to arrest just like Kissinger may be if he goes to Europe.
The second point is historically that whether the other side breaks the rules or not is not a defence. For example the Nazis adhered to the Geneva Convention in WW2 but the Russians were not a signatory to it, so they were able to attack civilian targets, etc.
I'm not taking sides in this just pointing out the facts of the matter.