In late December, South Korean activists stationed a statue of a young woman across from the Japanese consulate in Busan. Seated upright in a chair with her hands clasped in her lap, she stares intently, solemnly toward the consulate.

The statue offended Japan's government so much that this month it recalled its ambassador in Seoul and the consul general in Busan, and put major economic cooperation discussions on hold. Prime Minister Shinzo Abe himself urged the removal of the statue and called U.S. Vice President Joe Biden to complain. The statue represents a long-standing point of tension between Japan and South Korea — Korean women, often referred to euphemistically as "comfort women," who were trafficked into sexual slavery for the Japanese military before and during World War II. Japan and South Korea concluded a historic agreement at the end of 2015 that led the two governments to declare that, if the agreement was fully implemented, it would be considered a "final and irreversible" resolution to the comfort women issue.

Japan sees the statue as a taunt that violates the spirit of the agreement. But Japan's high-level response to an action by a civic group outside of Seoul's control makes a mountain out of a mole hill. It's an appalling error in strategic judgment that will endanger Japan-South Korea ties at a time when unity among U.S. allies is critical to deterring regional aggression. The United States must steer Japan toward a stance that reduces tensions and advances Japan-South Korea relations.