Leaders of S. Korea, U.S., Japan, China should stand united against N. Korea

South Korean President Park Geun-hye and U.S. President Barack Obama agreed at a summit in Washington on Thursday to faithfully implement the United Nations Security Council's sanctions on North Korea and step up pressure on Pyongyang. They also reaffirmed the joint defense posture between the two allies in line with the North escalating provocations such as a threat of a nuclear pre-emptive strike. At a trilateral summit among the two and Japanese Prime Minister Shinzo Abe, the leaders discussed ways to coordinate their own independent North Korea sanctions in order to maximize the synergies. President Park also had separate summits with the Japanese prime minister and Chinese President Xi Jinping.

Following the North's fourth nuclear test, the leaders of South Korea, the U.S. and Japan had discussed countermeasures over the telephone. For the first time since the test, they have met in person to send a strong warning against Pyongyang. President Obama asked Seoul and Tokyo to sign an intelligence-sharing pact within this year to cope with North Korean threats more efficiently. During the Lee Myung-bak administration, Seoul attempted to secretly sign the deal, only to cancel it after facing a strong public backlash. Currently, there is a trilateral pact among Seoul, Washington and Tokyo for sharing intelligence on North Korean nuclear and missile development. Still, the three allies need to strengthen their cooperation in leading pressures on Pyongyang. Despite many pending bilateral issues, including past history, between South Korea and Japan, they need to pursue an intelligence-sharing pact again. Security cooperation is one thing, history issues are another.

The New York Times reported that despite the U.N. sanctions, China's border guards pass goods transported to North Korea for a bribe of about 200 U.S. dollars. Concerns over China keeping a back door open to the North are not unfounded. Seoul and Beijing have differences over the proposed deployment of an advanced U.S. missile defense system in South Korea and simultaneous negotiation of the denuclearization of the Korean Peninsula and a peace agreement. The latest summit and working-level talks between South Korea and China should have made substantial discussions about ways to enhance the effectiveness of the North Korea sanctions.

The Nuclear Security Summit will begin on Friday where the U.N. and leaders of 52 countries possessing nuclear weapons or nuclear power plants will discuss ways to cope with nuclear terrorism. The biennial forum, which started in 2010, a year after President Obama advocated a "nuclear-free world," will also likely discuss the North Korean nuclear issue. The international community should unite once again and pledge to implement the North Korea sanctions so that Pyongyang's leader Kim Jong Un will realize the cold reality and do not misjudge the situation.

한기흥기자 eligius@donga.com