AP Photo

In 1998, North Korea caused widespread alarm by firing a rocket over Japan's main island of Honshu into the Pacific Ocean. It followed this provocative move by more long-range missile tests in 2006 and 2009.

Despite even stronger international opposition today, Pyongyang appears determined to press ahead with a plan to launch an observation satellite into orbit later this week using a similar but possibly improved version of the Taepodong-2 missile that it last tested in April 2009. North Korea calls the rocket Unha-3.

The United States and its Asia-Pacific allies, including Australia, Japan and South Korea, view the planned launch as a disguised test of a ballistic missile that one day could carry a nuclear warhead. They say it violates...