Moon Chung-in, special adviser to President Moon Jae-in on security and diplomacy, has caused controversy with his remarks to the effect that US forces may have to pull out of South Korea if a peace treaty is signed.

“What will happen to US forces in South Korea if a peace treaty is signed? It will be difficult to justify their continuing presence in South Korea after its adoption,” he said in an article published in the US magazine Foreign Affairs on Monday.

With criticism of the remarks mounting, President Moon said through his spokesman, “US Forces Korea is a matter of the South Korea-US alliance. It has nothing to do with signing a peace treaty.”

The spokesman also said that “chief of staff Im Jong-seok has called special adviser Moon to ask him not to cause any more confusion with the president’s position.”

This is not the first time that special adviser Moon has made controversial remarks ahead of government decisions.

His remarks have often caused controversy, followed by Cheong Wa Dae downplaying his comments as just personal opinions. However, some of his comments have later become reality.

For instance, he caused a stir when he argued that the US and South Korea should scale down their joint military exercises, but eventually the drills were scaled down during the PyeongChang Winter Olympics.

He also sparked controversy by raising procedural issues regarding the deployment of the Terminal High Altitude Area Defense anti-missile system. Afterward, Cheong Wa Dae instructed an environmental impact assessment of the system.

One cannot but suspect that the issue of stationing US forces in Korea may follow a similar course, too. Some speculate that Cheong Wa Dae downplayed the controversy hurriedly out of concern that it might affect thawing inter-Korean relations.

It is not right to forbid special adviser Moon from expressing his opinions as a professor. And yet it is problematic for him as a presidential special adviser to express opinions that are not the government’s policy on such an important issue as what will become of the USFK.

There is a high possibility that the withdrawal of the USFK will be mentioned eventually in the path toward a peace regime on the Korean Peninsula.

At the moment, North Korea has not mentioned the matter, but there is no guarantee it will keep doing so. Furthermore, one cannot exclude the possibility that China and Russia may demand the withdrawal in order to contain the US’ influence in Northeast Asia.

However, these scenarios should only come after the North dismantles its nuclear program completely and irreversibly, and a peace regime is established. Even at that point, the continuing presence of US forces is likely to remain justified for the security of South Korea, which is surrounded by bigger neighbors seeking hegemony.

The US troops in Korea are the essence of the US-Korea alliance, so the disappearance of justification for their presence here amounts to the breakup of the alliance.

Considering military tension with neighboring powers, the significance of the USFK as a balancing weight in Northeast Asia must not be disregarded.

Seoul and Washington must not use the withdrawal of the USFK or a reduction in scale as a bargaining chip to gain concessions from the North.

Kim Jong-il, the late North Korean leader, agreed to the continued stationing of the USFK during an inter-Korean summit in 2000. So far, his son, Kim Jong-un, has not demanded their withdrawal.

Special adviser Moon’s remarks are improper and wrong, as they could cause confusion to efforts to denuclearize the Korean Peninsula.

Of course, it is a problem that he is a loose cannon, but Cheong Wa Dae’s attitude toward him is hardly understandable.

Presidential chief of staff Lim warned him not to cause confusion, but that was all. Cheong Wa Dae said he was a “professor who enjoys freedom of thought and expression.” President Moon says he appointed Moon Chung-in as his special adviser to seek his help in exercising political imagination, but his imagination went too far this time.

If President Moon has an unshakable belief in the USFK, a warning is not enough.