Why do U. S. and the North Korea each see the other country as a threat?

north Korea has been the poster child for rogue states for over five decades. It has pursued a nuclear weapons program, constructed and exported ballistic missiles, sponsored terrorist acts, allegedly participated in the drug trade and counterfeiting, and posed a continuous threat to U. S. allies and interests, resulting in the stationing of U. S. forces in South Korea and Japan. But it has also been the subject of a policy experiment.