The following is an excerpt from Will Marshall’s column in today’s U.S. News & World Report:

Engagement with North Korea has been a bust—at least in South Korea’s eyes. In sinking the South Korean warship Cheonan, the regime in Pyongyang also torpedoed the South’s “sunshine policy” of humanitarian aid and economic investment in the North. Let’s hope the incident also shatters some illusions in Washington.

South Korean President Lee Myung Bak said the attack, which killed 46 sailors, has awakened South Koreans to “the reality that the nation faces the most belligerent regime in the world.” Seoul moved swiftly to seal the border, freeze trade, ban North Korean ships from its territorial waters, and designate the North as its archenemy. Bak’s militant response, however, seems to have rattled many South Koreans. Instead of rallying around the government, voters last week handed his Grand National Party a stinging defeat in local and regional elections. The prosperous South may no longer believe that Pyongyang can be tamed by economic blandishments, but young Koreans especially want to defuse the crisis.

The Obama administration is standing in solidarity with South Korea and pressing China to support new United Nations sanctions against North Korea. Secretary of State Hillary Clinton was recently in Seoul, where she reaffirmed the U.S. policy of “strategic patience.” Officials traveling with her said there will be no push to restart nuclear disarmament talks. “What we’re focused on is changing North Korean behavior,” the Washington Post quoted one official as saying.

Patience, no doubt, is a virtue in dealing with North Korea’s volatile dictator, Kim Jong Il. But it is not a policy. The United States has been trying to change the regime’s behavior since the Cold War ended, with little to show for it. Despite periodic bouts of U.S. engagement, multilateral diplomacy, and economic assistance, things have gotten worse. North Korea has developed and tested nuclear bombs, aided Syria’s clandestine nuclear program, sold missiles to Iran, and run a counterfeit-dollar racket, all while starving millions of its own people.

So what should be the strategic aim of U.S. policy toward North Korea?

Some foreign policy “realists” seem to believe that, if only the United States and its international partners can cobble together the right mix of economic incentives and diplomatic pressure, Pyongyang will eventually come to its senses. But North Korea offers a perfect illustration of realism’s blind spot—its inability to grasp the connection between the nature of regimes and their external conduct.

Read the full column at U.S. News & World Report.

Photo credit: US Army Korea – IMCOM