Last week, South Korean Prime Minister Lee Nak-yon traveled to Japan to attend Emperor Naruhito's enthronement ceremony and met with Prime Minister Shinzo Abe. Lee is widely seen as a friend to Japan, and his visit appears to signal Seoul's readiness to improve relations with Tokyo. Still, at this time, little to no progress has been made on the simmering trade war and historical grievances that once again threaten to overwhelm Japan-South Korea relations.

Despite sitting squarely within range of North Korea's nuclear arsenal and sharing a vital interest in meeting this threat together, Japan and South Korea have plunged into a heated showdown over history and trade. A 2018 South Korean court decision ordering compensation by Japanese companies for wartime labor during World War II, inflammatory rhetoric following Russian intrusion into airspace over the contested Takeshima islets and mounting trade tensions have propelled relations between Japan and South Korea to their lowest point in decades.

If Japan and South Korea are unable or unwilling to set aside their differences to ensure their own security in the face of the North Korean threat, what will happen to the U.S.-Japan-South Korea trilateral relationship if the North Korea issue is resolved?