When the South Korean corvette Cheonan sank a year ago, there was great uncertainty over its cause. Although North Korea was immediately suspected, Seoul initially downplayed that likelihood. Instead, a series of possible scenarios were suggested, including a North Korean mine inadvertently floating down from the north or even a Korean War-era U.S. mine.

Eventually, a multinational investigative team reported that strong forensic evidence pointed “overwhelmingly to the conclusion that a torpedo was fired by a North Korean submarine. There is no other plausible explanation.”

Pyongyang’s Motivations

North Korea was driven to attack the Cheonan by several factors. Pyongyang wanted to retaliate for its humiliating defeat by South Korea in a November 2009 naval clash. Realizing its surface fleet was no match for the South Korean navy, the regime needed to engage asymmetrically by using a submarine in a sneak attack. North Korea would also seek tactical advantage by using military confrontations in the West Sea to undermine the legitimacy of the Northern Limit Line, South Korea’s claims of sovereignty, and to intimidate Seoul from continuing military exercises in the area.

Attacks near the NLL are also a tactical tool to further North Korea’s strategic goals. Acts of military prowess enable North Korea to demonstrate that it will not be cowed by its opponents, enable Pyongyang to bargain from a position of strength, and reestablish its relevance on the international stage.

Pyongyang typically raises tensions as an effective means to secure negotiating leverage and wring concessions from its opponents, such as forcing the United States and South Korea to abandon pressure tactics, including sanctions. The regime saw that its long-range missile and nuclear tests in 2009 did not achieve its foreign policy objectives and likely felt compelled to conduct even more provocative, high-risk behavior.

The dual North Korean attacks on the Cheonan and Yeonpyeong Island also provided a domestic propaganda windfall to solidify the ongoing leadership transition from Kim Jong Il to his son Kim Jong Eun. The leadership succession was a factor in North Korea’s provocations, but was merely one component. North Korea has repeatedly engaged in such provocative behavior in the past without any succession underway.

South Korean Progressives Denying the Evidence

South Korean progressives vehemently rejected the multinational investigation team’s clear, comprehensive, and compelling conclusions about the Cheonan sinking. For to accept the evidence would undermine many of the myths they had fabricated about the North Korean regime. Instead, they claimed that the multinational report was merely the fabrication of President Lee Myung Bak. Some even asserted that the United States Navy had sunk the Cheonan.

Polls showed that 70 percent of South Koreans believed North Korea was responsible for the Cheonan attack. Yet, despite the overwhelming evidence, 30 percent (equal to the percentage of South Koreans who identify themselves as progressive) claimed North Korea was not involved.

For years, progressives absolved North Korea of any responsibility for its provocations, violations, and intransigence by instead blaming U.S. and South Korean “hardline” policies. Their claims rang increasingly hollow, however, after North Korea did not moderate its behavior following the transition from George W. Bush to Barack Obama. Indeed, the regime’s firm rejection of Obama’s offered hand of dialogue through a series of provocations in 2009 caused a belated epiphany among experts that Pyongyang had always been to blame for the North Korean problem, not successive U.S. policies.

It has also been claimed that a one-track policy of returning to negotiations, offering concessions, and abandoning punishment for North Korean violations would resolve the nuclear issue and prevent provocations. Yet secret discussions underway in March 2010 which were making progress toward resumption of the Six Party Talks did not prevent Pyongyang from attacking the Cheonan. Similarly, South Korea was meeting secretly with North Korean officials in November (even discussing humanitarian assistance) when the regime shelled Yeonpyeong Island.

South Korean public attitude towards North Korea hardened after the Yeonpyeong Island attack. Pyongyang’s responsibility for shelling the island could not be denied and the deaths of civilians angered South Koreans far more than the Cheonan sinking had. However, some progressives still blamed Lee Myung Bak’s abandoning of the unconditional engagement strategy of his predecessors for North Korea’s unprovoked acts of war.

U.N. Never Fails to Disappoint

The U.N. Security Council’s timid reaction to North Korea’s blatant attacks on the Cheonan and Yeonpyeong Island, as well as the disclosure of a uranium facility that violated U.N. resolutions, was extremely disappointing, though not unexpected. After the publication of the Cheonan investigation report, it was hoped that China might be shamed into doing the right thing. In the past, Beijing had been willing to punish North Korea, albeit mildly, when Pyongyang’s belligerency crossed a line that even China could no longer condone or ignore.

Instead, China and Russia resisted a binding Security Council resolution, instead forcing the U.N. to produce a timorous presidential statement. The document merely “deplores the attack [and] loss of life and expresses deep sympathy and condolences to the victims,” but did not explicitly identify North Korea as the attacker, much less take any action. Once again, China and Russia abandoned the rule of law in favor of meekly maintaining the peace. A proper U.N. response would have been binding resolutions explicitly condemning North Korea and imposing additional punitive measures.

China criticized U.S. and South Korean responses to the attack more than it condemned the attack itself. Beijing vehemently protested U.S.–South Korean joint naval exercises in the West Sea, claiming they were a threat aimed at China. The Chinese leadership not only ignored the actual reason for the exercises (i.e., North Korea’s sinking of the Cheonan) but seems ignorant of the fact that, had they taken stronger action against North Korea, such exercises might not have been necessary.

Impact of the Attacks on Negotiations

North Korea’s attacks on the Cheonan and Yeonpyeong Island reduced already dismal expectations for success in improving inter-Korean relations and the Six-Party Talks. The Lee administration requires a North Korean apology for the attacks prior to moving forward on inter-Korean talks. Strong public support for the demand will affirm Seoul’s resolve on the issue. Pyongyang’s refusal was a primary factor for the collapse of South-North Korean military talks last month.

Washington stands by its ally, deferring any bilateral U.S.-North Korean discussions until Seoul feels its security concerns have been addressed by Pyongyang. The Obama administration sees the lack of any contact with North Korea as counter-productive but is currently unwilling to risk undercutting critical ally South Korea.

A lack of movement by Seoul and Washington will induce Pyongyang to again resort to provocative actions….or a more energetic charm offensive…or both.

Bruce Klingner is a Senior Research Fellow for Northeast Asia at The Heritage Foundation.