Chinese leaders often describe Beijing’s relationship with North Korea as close “as lips and teeth”, but as warm as bilateral ties appear, this is a relationship underscored above all by strategic necessity.On July 11, 1961, then Chinese Premier Zhou Enlai and North Korean leader Kim Il Sung signed the Treaty of Friendship, Cooperation and Mutual Assistance in Beijing. Sixty-five years later, the treaty remains in force, containing a mutual defence clause committing either side to assist the other if one comes under armed attack. It is China’s only formal military alliance, underlining the treaty’s importance, but much has changed since it was signed.A sign of the continued importance of this treaty came this week, with a three-day visit by North Korea Premier Pak Thae Song to Beijing to celebrate the friendship treaty.But during the past 65 years, China has transformed itself from an impoverished revolutionary state into the world’s second-largest economy, while North Korea remains isolated and heavily sanctioned.Yet their alliance has survived the Cold War, China’s economic opening to the world, the collapse of the Soviet Union and decades of tension over Pyongyang’s nuclear weapons programme.Why has it lasted through these? Neither side can afford to let it fail.China wants stabilityThe China-North Korea relationship was forged during the Korean War, when United States-led forces advanced towards Chi …
