The meeting of U.S. and Japanese leaders in Pearl Harbor will be a reminder of the remarkable journey that transformed the two countries from adversaries to allies.

Ten years after North Korea’s first nuclear test, sanctions and negotiations have done little to quell the regime’s ambition of becoming a nuclear weapons state.

Absent evidence of N. Korea’s involvement, S. Korea’s response to the recent sinking of one of its ships has been measured. But public anger about the incident will impact June elections and increase…