The standoff over North Korea’s nuclear program has long been shaped by the view that the United States has no viable military option to destroy it. Any attempt to do so, many say, would provoke a brutal counterattack against South Korea too bloody and damaging to risk. That remains a major constraint on the Trump administration’s response even as North Korea’s leader, Kim Jong-un, approaches his goal of a nuclear arsenal capable of striking the United States. On Tuesday, the North appeared to cross a new threshold, testing a weapon that it described as an intercontinental ballistic missile and that analysts said could potentially hit Alaska.
