North Korea seems very keen of late to let everyone know that it is prepared to start a global thermonuclear war. The United States is taking the threat seriously, deploying antiballistic missile defenses along the Pacific Coast, and South Korea is threatening a "strong response in initial combat without any political considerations." There is some question as to whether North Korea is technically capable of actually waging such a war, and it seems that nobody has told Kim Jong Un, North Korea's Supreme Leader, my new favorite joke:

Q. Why did the chicken cross the road?
A. To escape North Korea's long-range missiles.

In 2001, it didn't seem that Kim Jong Un's fingerprints might one day adorn the red button. In those heady days, a different Kim was in line for the throne: Kim Jong Nam (above right), the eldest son of Kim Jong Il. Things went bad for Kim Jong Nam when he was detained at Narita International Airport in Tokyo. The charge: traveling with a fraudulent passport. Specifically, he attempted to pass himself off as a Dominican named Pang Xiong (which translates as "Fat Bear" in Chinese). Japanese authorities, who know a fake Dominican when they see one, deported the heir apparent of North Korea to China.

Kim Jong Nam and his immediate family were attempting to visit Tokyo Disneyland.

All of this was pretty embarrassing for Kim Jong Il, the Shining Star of Paektu Mountain, who thus canceled his own planned Chinese excursion. Kim Jong Nam quickly fell out of favor with his father, and was replaced by Kim Jong Un in the line of succession.

Kim Jong Nam and Kim Jong Un are half-brothers. The older brother was born to Song Hye-rim, mistress of Kim Jong Il. The younger of the two was born to Ko Young-hee, a Pyongyang opera star. There is a middle brother — Kim Jong Chol — but Dear Leader considered him too feminine to lead a manly state like North Korea.

Life in exile
These days, Kim Jong Nam reportedly lives in China, and makes frequent, extended visits to Macao, the Vegas of Asia. He is believed to have a pretty hearty appetite for booze and women. Officially, he has not defected and still lives in North Korea, though he didn't bother to attend Kim Jong Il's funeral, nor did he attend Kim Jong Un's coronation. There are reports that Kim Jong Nam is opposed to such hereditary transfers of power, and believes North Korea must reform or perish. "As a matter of common sense, a transfer to the third generation is unacceptable," Kim Jong Nam allegedly wrote in an email. He's not bullish on his half-brother, either. "The power elite that have ruled the country will continue to be in control ... I have my doubts about whether a person with only two years of grooming as a leader can govern."

His ongoing relationship with North Korea is "a very sensitive question, I can not answer."

As for his family life, we know that his mother was eventually exiled by Kim Jong Il, and that she died alone in Moscow. Kim Jong Nam's son attends a private high school in Mostar, Bosnia. (The son's name is Kim Han Sol.)

The upshot is that Kim Jong Nam was passed over for having, in his father's view, "less than reliable" judgment. Which means that Kim Jong Un, who is threatening to bring about a nuclear apocalypse, was considered the dependable one. All this because Kim Jong Nam wanted to go to Disneyland. If only he'd showed a little more restraint, Disneyland would have come to him.

More from Mental Floss...

10 things you might not know about North Korea

* 7 things I learned reading North Korea's newspaper

* Kim Jong-un wins 'Sexiest Man Alive': How The Onion tricked a Chinese newspaper