“We are about to run an experiment,” the international-relations scholar Robert Jervis recently observed of the Trump presidency. Scholars of international politics, he wrote, “bemoan the fact that our sub-field cannot draw on the experimental method.” But with an American president whose stated views on international relations differ so dramatically from those of his recent predecessors, even while many features of the international environment Jervis has studied for decades remain constant, “now we can.”
An important piece of the experiment has been ongoing for weeks as the Trump administration confronts the gathering threat of North Korea’s nuclear and missile programs. Kim Jong Un’s regime is now estimated to have as many as 20 nuclear warheads and could soon be able, if it isn’t already, to make some to fit on the missiles necessary to deliver them. The North has been accelerating missile tests—recently lobbing four in the direction of U.S. bases in Japan—in what the arms-control expert Jeffrey Lewis has called a practice run for a nuclear attack. In a New Year’s speech, Kim declared his country was in the final stages of developing an intercontinental ballistic missile (ICBM) capable of reaching the United States, a feat that Trump declared, via tweet, “won’t happen,” shortly before the U.S. accelerated the deployment of a missile-defense system to South Korea and kicked off annual joint military exercises with the South. On a visit to Seoul on Friday, Secretary of State Rex Tillerson left open the option of a military strike to prevent the weapons-development program from advancing too far, vowed to defend allies in the region, and ruled out negotiations with the North.