First, it is possible that Kim Jong Ill's regime could continue its provocations and finally miscalculate. South Korea could be backed into a nationalistic corner and be forced to escalate. In the past -- as in the sinking of the Cheonan -- North Korea has often implausibly denied its culpability, allowing much of the South Korean public to close its eyes and pretend. When shells fall on civilians in broad daylight, convenient illusions are dispelled. South Koreans had a visceral response to the deaths and evacuations, forcing President Lee Myung-bak to apologize for his initially supine response and to promise greater (though unspecified) vigor in the future. It is not inconceivable that North Korea might push past some invisible tripwire of South Korean pride, drawing the United States into the resumption of a shooting war.
A second outcome seems more likely. North Korea could find that its strategic calculations are correct: That none of its studied provocations will be enough to cause serious consequences. That South Koreans simply want to enjoy their well-earned prosperity instead of engaging in a heroic struggle that could destroy much of Seoul. That China still wants a buffer state on its border, no matter how dangerous and poorly run. That America, despite its past commitments, has no intention of renewing its part in Harry Truman's unended war.
But at some point this campaign of North Korean escalation becomes unsustainable for America. "The North Korean side," says Eberstadt, "may eventually manufacture a crisis with a conventional attack on a U.S. base or target. Then the American president will have a choice: meeting American security responsibilities, which may involve a generalized war, or a continuation of no response, no penalty -- undermining the credibility of the U.S. alliance with South Korea. The U.S. might be seen as a missile magnet by South Koreans, causing an upswell that compels our exit."
There is, however, a third possible outcome that has not been considered seriously enough -- an option other than possible war or strategic humiliation. South Korea, America and Japan, employing their technology and vast wealth, could attempt to undermine the North Korean regime from within. An aggressive, sustained campaign to break the North Korean information embargo, expose the barbarity and corruption of the regime to its own people, promote the work of dissidents and defectors, and encourage disloyalty among North Korean elites may or may not work. But the alternatives are increasingly unattractive.