Iran has little capacity to deploy force. Its strategic doctrines are defensive, designed to deter invasion long enough for diplomacy to set it.

Control is the source of strategic power.

The invasion of Iraq, particularly, gave a big shot in the arm to the jihadi extremists.

Over the years, there have been a series of concepts developed to justify the use of force in international affairs for a long period. It was possible to justify it on the pretext, which usually turned out to have very little substance, that the U.S. was defending itself against the communist menace. By the 1980s, that was wearing pretty thin.

The deceit and distortion surrounding the American invasion of Vietnam is by now so familiar that it has lost its power to shock.

To say that the United States has pursued diplomacy with North Korea is a little bit misleading. It did under the Clinton administration, though neither side completely lived up to their obligations. Clinton didn't do what was promised, nor did North Korea, but they were making progress.