https://www.wired.com/story/donald-trump-united-nations-north-korea/
One can trace that paranoia back to the Korean War. In 1950, then-US president Harry Truman said that he was prepared to authorize the use of nuclear weapons to end the conflict. Ever since, North Korea has “lived under US threat perception,” says Jenny Town, managing editor of North Korea watchdog 38 North and assistant director of the US-Korea Institute at Johns Hopkins School of Advanced International Studies.
“They point to several different actions and signals along the way, and they use this as a justification for why they need nuclear weapons, in order to deter the United States from any preemptive attack,” says Town. “They’ve seen this happen in the past, with Iraq, with Lybia. Early in the Trump administration they saw the bombing of Syria and Afghanistan. They’re trying to prevent this from happening to them.”