North Korea is ruled by a murderous totalitarian government that has committed acts of terrorism. But that government has been willing to make arms agreements with the United States in the past, and it is the U.S. government that has broken these agreements.
The first agreement was the 1953 Armistice that ended the Korean Conflict. Under this agreement, the two sides agreed to stop fighting, pull back, respect and demilitarized zone and not introduce any new weapons into the Korean peninsula, pending signing of a peace treaty.
That is, each side could replace weapons, rifle for rifle and tank for tank, but they couldn’t increase the total number of weapons or introduce new weapons. The U.S. renounced that part of the treaty in 1958 by bringing atomic weapons to South Korea.
Now, you can make the argument that this action was necessary to preserve the balance of power. And later on, the North Koreans were discovered to have dug tunnels under the DMZ for the purpose of sending spies and agents into South Korea. But still: It was the United States, not North Korea, that broke the terms of the Armistice.
Sometime in the 1980s, North Korea began work on a nuclear bomb. In 1994, President Bill Clinton sent ex-President Jimmy Carter to North Korea, where he persuaded the North Korean government to shut down its plutonium test reactor and put it under the control of international inspectors. In return, the North Koreans got shipments of oil for its power grid and two light water reactors built by an international consortium. All this was supposed to lead to normal relations between the two countries—which didn’t happen.
In 2002, President George W. Bush canceled the agreement. His administration claimed the North Koreans were cheating, by working on a uranium bomb. The evidence for this is unclear, and the North Koreans claimed that the U.S. hadn’t fulfilled its part of the agreement.
Be that as it may, the North Koreans sent the inspectors home and resumed their work on a plutonium bomb. By 2007, they exploded their first nuclear device. Ending the agreement accomplished nothing.
The Bush administration resumed negotiations and arrived at a new tentative agreement to freeze nuclear weapons development at the new level. But President Barack Obama didn’t follow through. Maybe he thought that he didn’t have enough political capital to try to make peace with Iran, Cuba and North Korea, too.
Instead the U.S. government tried to pressure North Korea by means of economic sanctions. North Korea responded by doubling down on its nuclear weapons program.
Now President Donald Trump threatens “fire and fury”. The government of North Korea says that it will never give up its nuclear weapons so long as the United States is hostile and threatens North Korea with its own nuclear weapons. Which is a way of saying it might give up its nuclear weapons if the U.S. was genuinely willing to make peace.