The US government likes enemies lists. The one commonality among its enemies is that they don’t do what the US government wants them to do. From Philip Giraldi at strategic-culture.org:

Many American still long for the good old days when men were still manly and President George W. Bush was able to announce that there was a “new sheriff in town” pledged to wipe terrorism from the face of the earth. “You’re either with us or against us,” he growled and he backed up his warning of lethal retribution with an enemies list that he called the “axis of evil.”
The axis of evil identified in those days in the 2002 State of the Union Address consisted of Iraq, Iran and North Korea. Iraq, which had not yet been invaded and conquered by the American war machine, was number one on the list, with Saddam allegedly brandishing weapons of mass destruction deliverable by the feared transatlantic gliders that could easily strike the United States. Bush explained that “Iraq continues to flaunt its hostility toward America and to support terror. The Iraqi regime has plotted to develop anthrax and nerve gas and nuclear weapons for over a decade. This is a regime that has already used poison gas to murder thousands of its own citizens, leaving the bodies of mothers huddled over their dead children. This is a regime that agreed to international inspections, then kicked out the inspectors. This is a regime that has something to hide from the civilized world.”
North Korea meanwhile was described as “A regime arming with missiles and weapons of mass destruction, while starving its citizens” while Iran “aggressively pursues these weapons and exports terror, while an unelected few repress the Iranian people’s hope for freedom.”