I assume among the reasons to go into Iraq was to show the other (stronger) Axis of Evil countries, as well others (Syria, Libya) that the US was not a country to be trivled with. Thus, the administration maintained a hard line against these other countries, trusting that they would get the message from the manhandling Iraq was taking.
As with just about everything else this administration has tried, this failed miserably. Iran is doing its thing. North Korea? Well, since the hard line message wasn’t working, GW finally decided to try negotiations. But negotiations only work if you have something to negotiate. The only thing the Dear Leader of North Korea seems to want is to stay in power. There aren’t any big carrots you could offer someone like that(food for his people isn’t a carrot if he doesn’t mind seeing millions of them die), and there’s only one stick. Had negotiations taken place years ago, the stick would have been there. Because the administration waited until after they destroyed the stick, its not surprising that the Dear Leader thumbs his nose at the thumbs his nose at the world.