Political leaders on both sides of the Pacific must realize that the damage from deteriorating Japan-South Korea ties fundamentally undermines the U.S. alliance system in East Asia.

Yuki Tatsumi, co-director of the East Asia Program at the Stimson Center in Washington, saying that disputes between Japan, South Korea and China are flaring up as U.S. President Donal Trump sits on the sidelines, focusing on his "America First" policy.

© Bloomberg