Moon’s split stance with China, US reveals fragility of his diplomacy

South Korean President Moon Jae-in visited China for the first time since taking office and conferred with his Chinese counterpart, Xi Jinping.
Concerning North Korea’s nuclear and missile development, which was a focal point of the summit talks, the two leaders agreed to seek a peaceful solution through dialogue and not allow a war on the Korean Peninsula.
 Regarding pressure on Pyongyang to lead it into dialogue, the bilateral agreement was limited to implementation of sanctions resolutions adopted by the UN Security Council.
US President Donald Trump is asking China to stop its supply of crude oil to North Korea. Japan is aiming to maximise pressure on Pyongyang. It is problematic that China and South Korea failed to agree on concrete sanctions against the North, thus revealing their different levels of enthusiasm toward sanctions by the US and Japan.
China and South Korea did not issue a joint statement as is usually done in times of a state guest visit. This is because they could not bridge the rift over deployment of the Terminal High Altitude Area Defence (THAAD), a cutting-edge missile defence system, to US military forces stationed in South Korea.
China opposes the THAAD deployment, and has been continuing retaliatory measures. Beijing has been restricting the activities of South Korean firms operating in China and controlling group tours of Chinese to South Korea.
Xi clearly stated, “The Korean side is called on to deal with the issues appropriately.” This could be regarded as a blatant intimidation that lifting the retaliatory measures will require further concessions on the part of Seoul.
To comply with China’s intentions, South Korea at the end of October announced that it would not further deploy THAAD or take part in the US defence system. Seoul also stressed that “the Japan-US-South Korea security cooperation will not develop into a military alliance”.
Moon’s judgement that the rift could be healed with these assurances was optimistic.
China opposes the deployment because it is wary about the possibility of THAAD radars being used by the US military to monitor China’s ballistic missiles.
THAAD missiles are originally designed as equipment to protect South Korea from the threat of North Korea. Moon must realise that he is allowing China’s interference and harming the sovereignty of his own country.
It cannot be overlooked that Moon’s statements during his China visit made transparent his intention to form a united front with China in dealing with the issue of historical perceptions against Japan.
Referring to the Nanjing Incident by former Japanese forces, Moon said, “The South Korean people have sympathy for the distress suffered by Chinese people.” This was apparently aimed at emphasising that China and South Korea suffered harm from Japan’s pre-war militarism.
During a visit to the inland city of Chongqing, Moon visited the site of the building of the Provisional government of the Republic of Korea, which became the stronghold for the independence movement during Japan’s colonial rule of the Korean Peninsula. 
Does he want to propagate the self-righteous perception of history that South Korea won liberation from colonial rule?