War has swept away the regime of Saddam Hussein, but the most urgent nuclear proliferation challenge remains unresolved.

In December 2002, the Bush Administration issued its National Strategy to Combat Weapons of Mass Destruction. This document reiterated a line that had been used on other occasions over the previous year by President Bush: “We will not permit the world’s most dangerous regimes and terrorists to threaten us with the world’s most destructive weapons.” This strong language (“We will not permit…”) is meant to signal Washington’s determination to prevent the spread of weapons of mass destruction—especially nuclear weapons—to hostile parties, whether states or terrorists. The “National Strategy” also declares unambiguously that the United States is prepared to use force, preemptively if necessary, in support of that objective.

The war in Iraq was, at least in part, an example of this Bush doctrine in action. The Bush Administration’s concern over Saddam Hussein’s apparently insatiable appetite for WMD, weapons of mass destruction, constituted a major element in the case for war. Iraq’s failure to comply with the disarmament provisions of U.N. resolutions dating back to the 1991 Gulf War was the cause of the international crisis that, after much diplomatic wrangling, led to war. Ultimately, Washington concluded that regime change was the only reliable and durable solution to the threat posed by Baghdad’s relentless pursuit of WMD.

Now, however, the Bush doctrine must cope with a much harder test. In the months since October 2002, the regime in North Korea has taken a series of stunningly provocative steps that represent a flagrant challenge to the Bush Administration’s nonproliferation policy. While Washington was obsessed with Iraq, Pyongyang admitted that it has an illicit nuclear weapons program, threw out international inspectors, formally renounced its international obligations under the Nuclear Nonproliferation Treaty (NPT), took possession of and relocated nuclear materials that were formerly under international supervision and restarted the nuclear reactor that will enable it to produce more weapons-grade nuclear material in the future.

Washington was in a quandary over what to do. Preoccupied with Iraq, the Bush Administration had no interest in a simultaneous military crisis with North Korea, nor does the military option seem as viable on the Korean Peninsula given the vulnerability of Seoul to North Korean attack. But, as President Bush has commented emphatically, succumbing to blackmail by negotiating a deal that appears to reward Pyongyang’s illicit nuclear behavior is equally unattractive; indeed, the President has deemed this unacceptable. Washington has placed some hope in the possibility that multilateral pressure might bring Pyongyang to its senses and has viewed China—North Korea’s main international supporter and essential provider of economic aid—as the key player in forcing a satisfactory resolution of the crisis. Simultaneously, the Bush Administration has voiced expectations that the example of America’s military triumph in Iraq will send a clear and unambiguous coercive lesson to other hostile proliferators, who must understand that they should refrain from seeking WMD or risk the fate of Saddam’s Iraq.

These hopes and expectations were put to the test in trilateral talks in Beijing on April 23-24—and were resoundingly dashed. In the course of this meeting, the North Koreans unexpectedly and unprecedentedly claimed that they already possess nuclear weapons and suggested that they are willing to test them, use them and export them. They also reported that they have been reprocessing 8,000 spent nuclear fuel rods to extract from them the plutonium to build still more weapons. (Western experts estimate that North Korean might be able to build as many as six additional weapons with the plutonium from these fuel rods.) Whether Pyongyang’s claims are true is not clear, but what is certain is that the North Koreans could hardly have concocted a more brazen affront to the Bush Doctrine. Moreover, Pyongyang’s threats of nuclear misbehavior must be taken seriously given its penchant for brinksmanship, its tendency toward recklessness and its remarkably promiscuous proliferation record.

North Korea also indicated that it might be willing to abandon its nuclear program in return for a package of assistance and concessions from the United States. This suggestion was rejected almost immediately by President Bush. The United States is prepared to talk with North Korea in multilateral settings but it is in no mood to offer carrots. Hence diplomacy does not look hopeful. The Bush Administration seems inclined to find ways of pressuring North Korea—by urging the Chinese to cut aid, by interdicting North Korea’s illicit traffic in arms and drugs—so that the crisis can be resolved by coercion rather than bribery. So far, though, Pyongyang has responded to pressure with escalation rather than concession. If neither diplomacy nor pressure succeeds, then the options are reduced to two: either deploy the military or live with a nuclear North Korea. Only one of these options is consistent with the Bush Doctrine. Here, then, is a classic public policy conundrum: one big problem, no good options. Only the credibility of the Bush doctrine and the security of the United States are at stake.

Steven E. Miller is the director of the International Security Program at the Belfer Center for Science and International Affairs at the Kennedy School of Government.