Since the beginning of the year, North Korea has tested many missiles of various ranges, including an intercontinental ballistic missile last week.

With nuclear weapons atop these missiles, they become a genuinely serious, if not existential, threat to South Korea, Japan and the United States.

But they most dramatically alter Japanese security. And at some point, Japan will be forced to develop a counter-strategy, likely some mix of missile defense, a substantially expanded missile force of its own — and possibly nuclear weapons.