Most significant, the two have nuclear programs that risk destabilizing their regions and threaten an already fragile global nonproliferation regime.
"Both are countries that tend to have foreign policies or exhibit international behavior that is a source of concern and friction with the international community, and both are pursuing nuclear weapons and policies that bring them into conflict with the US and America's allies," says James Dobbins, a former US diplomat who is now director of the International Security and Defense Policy Center at the RAND Corp. in Arlington, Va. "There are a number of countries out there with one or the other of these factors, and they are less of a concern. It's the combination of the two that really makes North Korea and Iran stand out."
It is these characteristics that make North Korea and Iran "rogue states," a term Mr. Dobbins says is fair because it "aptly depicts an unwillingness to comply with broadly accepted standards of international behavior and respect for human rights."
But others say such labeling is an oversimplification of two very different challenges that could make solving them more difficult. "It creates barriers to understanding rather than facilitating understanding and therefore a way forward," says Andrew Bacevich, an international-relations expert at Boston University.