LONDON — In mid-June, the trailer for Seth Rogen and Evan Goldberg’s comedy “The Interview” hit the Internet. The movie, due in October, stars James Franco and Mr. Rogen as an American talk-show host and his producer, recruited to assassinate the North Korean leader, Kim Jong-un, while in Pyongyang to interview him. The trailer features Mr. Franco and Mr. Rogen riding tanks, the actor Randall Park as Kim Jong-un smoking a missile-size cigar, and a discussion, played for laughs, of reported North Korean propaganda claims that none of the Kim leaders defecate.

Within days, the North Korean Foreign Ministry slammed the film as “intolerable,” as well as “the most blatant act of terrorism and an act of war,” and threatened “merciless” retaliation if it was released. The next day the North Korean military launched three short-range ballistic missiles into the sea, as if to hint, “See what I mean?”

The lesson: Never underestimate the power of marijuana in Hollywood, and phallic jokes about rockets and cigars.

It seems absurd for the leader of a nuclear state to be so incensed over an anarchic comedy by the guys who brought you “This Is the End” and “Pineapple Express.” But movies have held inordinate importance in North Korean politics, beginning even before the country’s founding in 1948. One of the earliest actions by Kim Il-sung, called Great Leader, was to create a Soviet-supported national film studio, where he gave filmmakers and crews preferential food rations and housing. His son, Kim Jong-il, called Dear Leader, was a film buff who owned one of the largest private film collections in the world and whose first position of power was in running the regime’s propaganda apparatus, including its film studios. For over 20 years he micromanaged every new North Korean film production, as writer, producer, executive and critic; to his people, he is still known today first and foremost — thanks to propaganda rather than any real talent or skill — as the greatest creative genius in North Korea’s history.