President Moon Jae-in of South Korea might have been gleeful meeting North Korean leader Kim Jong Un in Pyongyang on Tuesday. But Americans shouldn’t be.

After all, this meeting is just the latest signal that the South Korean leader has abandoned the fundamental U.S. principle for negotiations with North Korea: maximum economic and diplomatic pressure that reduces alongside verifiable denuclearization and disarmament. Instead, supported by Chinese nudging and subdued by the belief that rising tensions with North Korea risk South Korea’s very survival, Moon is pushing appeasement.