What’s more, shooting down the missile is a proportionate, limited and clearly defensible action. It is neither aggressive nor provocative. It can be justified with reference to U.N. resolutions and long-standing self-defense pacts with Asian allies.

This is not like previous missile tests, where Washington and its allies did nothing. With the missile traversing Japanese islands and American bases and aiming for the waters of Southeast Asia, there is a much higher chance of something going wrong and the missile falling on the territory of other nations.

Shooting it down then also prevents further possible escalation, especially considering the dramatically heightened concern of both South Korea and Japan. For its part, the South remains prepared to respond with overwhelming military force to any North Korean provocation, a legacy of Pyongyang’s sinking of a South Korean naval ship and the shelling of an island in 2010. If the missile aborts over South Korean territory, a war could break out. Seoul has indicated it may shoot down the missile, as has Tokyo—the missile passes over Okinawa and other Japanese territory.