If South Korea's new president, Moon Jae-in, entertained for a moment the idea that North Korea would give him an opportunity to test his readiness to engage, those hopes died Sunday when Pyongyang tested a new intermediate-range missile. The test was a success and raises the stakes for dealing with North Korea. It is not a crisis, but it is a slap in the face to Moon as well as every other government that hopes to get North Korea to act in accordance with international rules and the wishes of the rest of the world.

North Korea has conducted six sets of missile tests in 2017 — nine missiles in total — with varying results. The last test, in April, was a failure: The missile broke up in midair shortly after takeoff. Sunday's test was a success, however. What is thought to have been an intermediate-range missile flew a claimed 787 km in about 30 minutes before crashing into the Sea of Japan. Experts were surprised by the launch, which represents a level of performance hitherto unattainable by the North. The Hwasong-12 flew higher and longer than any previous North Korean missile. If launched on a trajectory designed to maximize distance, it could have traveled 4,500 km, which would put U.S. bases in Guam within range.

Equally, if not more important, the missile landed in a narrowly defined area, between South Korea's air defense identification zone (ADIZ) and that of Japan, which suggests targeting capabilities are developing as well. Finally, North Korea claims the test demonstrated that it had mastered re-entry technology, which would allow a warhead to survive the flight and detonate on impact. All in all, it is a troubling development. Experts fear that this test represents a big step forward in the drive to develop an intercontinental ballistic missile that would threaten the mainland United States.