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It took barely two weeks for North Korea to play its old game of bait and switch, this time gutting the Feb. 29 "Leap Day Agreement" with the Obama administration that promised a moratorium on nuclear and missile testing. In an Ides of March announcement, Pyongyang revealed it would conduct a "satellite launch" on April 15, which coincides with the 100th anniversary of the birth of Kim Il Sung, founder of the North Korean regime.

Such a disguised missile test not only violates U.N. resolutions, it forces U.S. President Barack Obama either to swallow a brazen insult or scrap a deal he hoped would show his leadership in resolving the long-running nuclear crisis. The president must resist the temptation to turn the other cheek. If he fails to do so, North Korea's new leadership...