War talk by a young dictator is making the world jittery. Kim Jong-un, who inherited the leadership of communist North Korea in December 2011 when his father died after 17 years in power, threatens nuclear missile attacks against neighboring South Korea and even the United States. He's angry over U.S.-South Korean military drills, a yearly routine, and a new round of United Nations economic sanctions because of a nuclear weapons test in February that was the country's third. Those underground tests violate an international ban. When North Korea last week announced plans to restart a nuclear reactor that was shut under an international agreement, U.S. Defense Secretary Chuck Hagel described the dictatorship as "a real and clear danger and threat."

The situation has roots that date back more than 60 years. Kim Jon-un's grandfather invaded South Korea in 1950, setting off three years of war in which the U.S. defended South Korea. The conflict was followed by an uneasy truce that has lasted six decades and now is being pushed to the breaking point by a leader believed to be just 28 or 29 years old.

Although it's a poor nation with chronic food shortages, North Korea has the world's fifth-largest army -- more than 1.1 million soldiers under arms and 4.7 million on reserve, according to the International Institute for Strategic Studies. Most of the force is pointed at South Korea. According to the London-based institute, it has 8,000 artillery systems and 2,000 tanks at the demilitarized zone on the border. Half of South Korea's 50 million people live within short-range striking distance and the capital, Seoul, is just 30 miles from the border. The U.S. Navy last week moved radar and anti-missile systems towards North Korea. U.S. jet fighters and two bombers flew over South Korea as another sign of readiness to defend our ally.

Writer says: "Nothing is for certain when it comes to North Korea, but the chances are good it will shoot something up to restore its dignity – perhaps a South Korean fishing boat or another South Korean navy vessel." – Robert Baer, Time magazine columnist, author and former CIA field officer

U.S. expert says: "This is a leader for whom we know as little as anyone in the world. He's not widely traveled. He's very, very young." -- P. J. Crowley, former U.S. assistant secretary of state

South Korean expert says: "It is difficult to keep North Korea under control despite the fact that the U.S. and South Korea are superior in military force, because they know that we won't use force first." -- Park Syung-je, Asia Strategy Institute analyst