In the 1976 psychological drama “Taxi Driver,” Robert De Niro plays a socially outcast cab driver. In a real-life drama today, North Korea’s Kim Jong Un is an internationally isolated world leader. In both roles, these characters communicate messages delivered with a sense of bravado, taunting a non-existing threat.

In an iconic scene in the movie, De Niro, alone in his room, is on an adrenaline high precipitated by insomnia. Looking in the mirror, he challenges no one with, “You talkin’ to me? Well, I’m the only one here! You talkin’ to me?”

In North Korea, Kim Jong Un is on an adrenaline high due to the success of his country’s third nuclear test — this on a device purportedly smaller and lighter than the others and, thus, capable of placement into a long-range missile.

Issuing his challenge, the well-fed leader — a giant compared to his diminutive, underfed countrymen — warns he will take further steps if the United States maintains its “hostile approach” toward North Korea. Trying to create the illusion of a U.S. threat where none exists, Kim taunts an America perceived to be the lion from the Wizard of Oz — i.e., lacking the courage of its convictions.

Pyongyang knows there is nothing to fear from U.S. foreign policy toward the North — whether under a Republican or Democratic president, whether the talk is tough or not, whether sanctions were increased or lifted — for such policy has always failed to influence its conduct away from aggression and nuclear armament.

Years of U.S. and South Korean appeasement have only served to encourage it. As a result, for years, the United States and South Korea have repeatedly been victimized by unprovoked aggression. To this day, a U.S. warship remains in North Korean hands as a continuing reminder of it.

Past U.N. efforts to ratchet sanctions up on the North have been blocked by Pyongyang’s big brother — China — claiming it seeks to keep the peninsula “stable.”

But such protection by China of the North’s misdeeds only creates instability. As the North’s prime supplier of food and fuel, China should have had leverage to dissuade it from conducting its most recent nuclear test. It did not.

Thus, questions now arise over China’s ability to exercise control over the rogue state. Another big brother now flexes its muscle, apparently exerting greater influence over the North.