North Korea is a nuclear power. Here’s why the world just has to live with it.

First, it is inconceivable that North Korean leader Kim Jong Un would give up the weapon that places his nation in the exclusive global nuclear club. Pyongyang has invested so much and come so far to mature a nuclear program that provides it with an atomic deterrent and a means of intimidation. Second, history repeatedly shows that sanctions are unlikely to be fully enforced or sufficient to squeeze North Korea.

Washington and its allies must now come to the realization that it is time to adapt.

Adaptation has already begun. South Korea has made a multi-year commitment to increase its military budget and modernize its conventional forces. It has begun deploying longer-range surface-to-surface missiles and is acquiring U.S. F-35 strike aircraft. Seoul is talking with Washington about installing the sophisticated missile defense system Terminal High Altitude Area Defense or THAAD. Collectively, beefing up of its conventional forces bolsters Seoul’s deterrence capabilities.

Yet many in South Korea still fear that Seoul’s military buildup will not be enough. Some conservative legislators and others both in and out of government have called for the country to go nuclear. Were that to occur, Seoul would follow the path of several countries — the Soviet Union, Britain, France and Pakistan — that responded in kind to their adversaries’ possession of nuclear weapons.