August 2017 was a reminder of the scariest, and riskiest, days of the Cold War. All month long, Donald Trump and Kim Jong-un engaged in a bitter war of words that escalated into tit-for-tat displays of military might and ended with mutual threats of mass destruction. The tensions peaked on September 3 with Pyongyang’s stunning announcement that it had conducted its sixth, and largest, nuclear test—this time of a powerful hydrogen bomb—and had the capability to place the bomb onto an intercontinental ballistic missile. With the crisis spinning out of control, the opportunity for the diplomacy and negotiations promised by Trump’s foreign-policy team in recent months seemed to fade with each passing day.
Ironically, the spiral of events began with a hopeful sign on August 15, when Kim uncharacteristically backed down from a highly publicized plan to launch ballistic missiles toward the United States garrison island of Guam. His surprise decision drew approving comments from Trump as well as Secretary of State Rex Tillerson, who has been at the forefront of US proposals for diplomacy. He offered that Kim’s “restraint” might be enough to meet the US conditions for talks—a halt to nuclear and missile tests—that he recently laid out in a Wall Street Journal op-ed co-authored with Defense Secretary James Mattis.
But Kim, who has said he will negotiate only if the United States ends its “hostile policy and nuclear threats,” had warned that he would reconsider his missile tests “if the Yankees persist in their extremely dangerous reckless actions.” He was speaking of the US–South Korean military exercises launched on August 21 that, according to press reports, included training runs for a preemptive strike against the North as well as a computerized nuclear war game. To counter this show of force, Pyongyang test-fired three short-range rockets and followed up with a medium-range missile shot over the northern Japanese island of Hokkaido.
Predictably, Kim’s moves sparked a US counter-action—a practice bombing run over Korean skies by Guam-based supersonic B1-B Lancer bombers, aided by four stealth F-35B advanced fighter jets flown from the US Marine base in Iwakuni, Japan. Days later, the North announced that it had developed a hydrogen bomb that could be placed on an ICBM—and, as mentioned, promptly tested the device in a massive underground explosion. Trump responded with a tweet denouncing the North as a “rogue” nation. He then insulted South Korea by calling President Moon Jae-in’s preference for engagement “appeasement,” apparently ruling out the diplomacy sought by his top advisers.