The United States does not practice the old-style imperialism of conquest, the establishment of colonies, and the use of direct rule. Instead, U.S. imperialism consists of creating patron-client relationships with security dependents and enforcing that policy through a global network of military bases.
One of the problems a great power faces is how to handle situations where two or more allies quarrel and adopt antagonistic policies towards each other. The United States faces that challenge now, as Japan and the Republic of Korea (ROK) engage in escalating disputes involving both economic and security issues.
Continuing to demand that Pyongyang capitulate and accept total denuclearization is pointless. A settlement that limits North Korea's nuclear and missile capabilities is attainable, and it would substantially reduce the danger of war on the Korean Peninsula — something that would benefit the United States and global community.
Getting North Korea to give up its small nuclear arsenal and put itself at the mercy of security guarantees that the United States and its East Asian allies might offer is not a realistic or achievable goal. The Trump administration and the broader American political and foreign policy elite need to accept that reality.