Twice in a month Pyongyang has used provocations in an attempt to leverage the United States and South Korea away from their pressure tactics, including U.N. sanctions, against North Korea. This week, the North Korean regime dangerously escalated tensions by attacking a South Korean island in the first artillery strike since the Korean War.

Earlier this month, Pyongyang disclosed an extensive uranium enrichment facility to undermine support for international sanctions on the North Korean regime by raising fears of a nuclear breakout. Critics of U.N. sanctions will use both provocations to advocate for a hasty return to the six-party talks to prevent an expanded North Korea nuclear arsenal.

The Obama Administration should resist such advice and maintain the current two-track policy of pressure and conditional engagement toward North Korea. The U.S. should, however, press the international community to redress shortfalls in the current sanctions program to raise the cost to Pyongyang for yet another violation of U.N. resolutions.

Artillery Attack Another Unprovoked Act of War

The situation on the Korean Peninsula following the North’s artillery attack is tense but unlikely to lead to war. Seoul will be constrained by all the same factors that hindered a strong South Korean response to North Korea’s March 26 attack on the Cheonan naval ship.

South Korea fears that even a limited retaliatory attack could degenerate into an all-out conflagration. As with the attack on a South Korean ship earlier this year, Seoul and Washington realize how limited their military options are and how little leverage they have on North Korea.

Disclosure Validates Earlier U.S. Assertions

During a visit to the Yongbyon nuclear facility, Dr. Siegfried Hecker, former head of the Los Alamos nuclear laboratory, was shown an extensive array of 2,000 centrifuges producing low-enriched uranium. The U.S. scientist commented that he was stunned by the size and sophistication of the facility, which exceeded all predictions of North Korean progress on a uranium program.

Successive U.S. Administrations have asserted that North Korea began a uranium-based nuclear weapons program in the early 1990s. Indeed, in both 1999 and 2000, the Clinton Administration was unable to certify to Congress that North Korea was not pursuing uranium-enrichment capability. The U.S. intelligence community was unanimous in its 2002 assessment that North Korea had an active program to acquire materials for enriching sufficient uranium to develop weapons.

However, critics charged that the U.S. intelligence assessments were merely partisan fabrications of the Bush Administration. Dr. Hecker’s direct observations of the uranium enrichment facility provide irrefutable evidence of Pyongyang’s continuing efforts to develop parallel uranium- and plutonium-based paths to a nuclear arsenal.

Uranium Facility Heightens Proliferation Risks

Dr. Hecker concluded that the centrifuges could be readily converted to produce highly enriched uranium for nuclear weapons. Lee Un-chul, a nuclear scientist at Seoul National University, estimated that Pyongyang could produce one to two uranium weapons per year using 2,000 centrifuges. Capability would be even greater if North Korea has other undetected uranium enrichment facilities.

The newly identified uranium facility at Yongbyon not only provides North Korea with greater capabilities for increasing its nuclear weapons arsenal but also increases the risk of proliferating fissile material and nuclear technology. A U.N. task force concluded earlier this year that North Korea has continued to provide missiles, components, and technology to Iran and Syria since the imposition of U.N. sanctions.

Continued Need for Pressure Tactics

North Korea’s ability to expand its nuclear weapons programs despite international pressure will resurrect debate over the efficacy of sanctions. This debate is usually depicted in binary fashion—i.e., whether the U.S. should use pressure or engagement. The reality, of course, is that sanctions and engagement—along with economic assistance, military deterrence, alliances, and public diplomacy—are all diplomatic tools to influence the negotiating behavior of the other side.

Rather than being used in isolation, these tools are most effective when integrated into a comprehensive strategy utilizing all the instruments of national power. Sanctions and engagement, as well as the other tools, are a means to an objective rather than an end, a point often lost on those who claim that the mere resumption of negotiations is itself a success. Abandoning any component of national power reduces the effectiveness of U.S. foreign policy.

U.S. Should Strengthen Two-Track Policy

The Obama Administration should maintain its policy of North Korea fulfilling necessary preconditions prior to Washington agreeing to return to the six-party talks. It is important that North Korea first provide solid indications that it will actually abide by its previous commitments and address Seoul’s concerns over the heinous attack on the Cheonan.

The likelihood that Pyongyang received foreign assistance on the uranium program shows that it is past time for Washington to target both ends of the proliferation pipeline rather than restricting sanctions to only North Korean violators. U.N. and U.S. reluctance to target Iranian, Syrian, Burmese, and other government and private entities has hindered international efforts to constrain North Korea’s nuclear and missile programs.

Washington should also press China to more aggressively combat North Korean proliferation and be more assertive in pressuring Pyongyang to abandon its nuclear weapons ambitions. China’s expansion of both its official and private sector economic dealings with North Korea has undermined the impact of U.N. sanctions and removed the incentive for Pyongyang to return to the six-party talks, where economic benefits are conditioned on progress in denuclearization.

North Korea’s Deteriorating Self-Control

It is worrisome, if not frightening, how far Pyongyang is now willing to go to achieve its foreign policy objectives. North Korea appears to have abandoned previously self-imposed constraints on its behavior. Although this new brazenness could be related to the ongoing North Korean leadership succession, it may also reflect the regime’s growing desperation brought on by deteriorating economic and political conditions.

Although Seoul will likely exercise restraint in this situation, Pyongyang is venturing into new territory with its recent actions. North Korea’s willingness to engage in ever escalating provocative acts has created a tinderbox on the Korean Peninsula with a commensurate growing risk of miscalculation by either side. The Cheonan attack, the revelation of a uranium enrichment facility, and yesterday’s artillery attack shows that the previously static situation is unraveling.

Bruce Klingner is Senior Research Fellow for Northeast Asia in the Asian Studies Center at The Heritage Foundation.