Why Is Kim Jong-il Suddenly So Aggressive?

Actually, North and South Korean ships have been clashing for years.

By Fred Kaplan
Posted Wednesday, May 26, 2010, at 6:18 PM ET

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North Korea's recent sinking of a South Korean warship was not an inexcusable act of aggression that came out of nowhere. It was an inexcusable act of aggression that had been building up for many years.

Though it was little noted in U.S. news reports, the maritime border between North Korea and South Korea—known as the Northern Limit Line—has been a frequent scene of naval clashes and confrontations over the last decade.

The March 26 incident, which killed 46 South Korean sailors and wounded many more, is by far the deadliest of these attacks and fully worthy of the condemnation it's received from the Obama administration, the U.N. secretary-general, and other world leaders.