There was relief throughout East Asia as well as within the Bush administration when North Korea submitted its long-awaited declaration regarding its nuclear program. Granted, it was fourteen months overdue, and contrary to the commitment that Pyongyang had made to the other participants in the six-party talks in February 2007, it was far from complete.

Nevertheless, the Bush administration agreed to remove North Korea from the list of states that sponsor terrorism and to lift economic sanctions imposed under the Trading with the Enemy Act. Optimists in the United States and other countries exude confidence that the six-party talks will now move forward and ultimately produce a settlement ending Pyongyang’s quest for nuclear weapons. Indeed, a new round of talks just ended on Saturday with another promise from North Korea to permanently disable its nuclear program.

One hopes that the optimists are correct, but North Korea’s record does not inspire confidence. Over a period of more than two decades, Pyongyang has violated every agreement it has ever signed on nuclear matters. It is all too possible that Kim Jong-Il’s regime is merely stalling for time while it continues to build nuclear weapons, and that even if the diplomatic process leads to a paper agreement, North Korea will find a way to cheat yet again.

It is time to ask what the United States and North Korea’s neighbors in East Asia plan to do if the optimistic scenario does not pan out. In other words, what is “Plan B” if the six-party talks fail? There appear to be only four other policy options, and none is entirely appealing or without risk.

The first option would be to follow the suggestion of former Ambassador to the United Nations John Bolton and other hard-liners to impose stronger multilateral economic sanctions, and perhaps even establish an air and naval blockade. That strategy has several problems, however. Beijing is vehemently opposed to any new round of sanctions, and without Chinese cooperation, coercive economic measures would have little impact on Pyongyang.

Not surprisingly, Beijing is even more opposed to a blockade against its North Korean ally. Moreover, a blockade is considered an act of war under international law, and one hesitates to predict the reaction of the volatile North Korean regime. The last thing the United States and its diplomatic partners want to do is trigger a general war on the Korean Peninsula.

For that reason alone, the second option, launching air strikes against North Korean military targets, is far too risky. Pyongyang has enough artillery pieces to fire more than 300,000 shells an hour into the Seoul metropolitan area, home to some 50 percent of South Korea’s population. Moreover, if North Korea has produced nuclear weapons — and experts estimate it may already have built as many as seven or eight — it might launch those weapons against targets in South Korea and Japan. Granted, if Pyongyang escalated matters to a full-scale war in East Asia, the regime would not survive the conflagration, but that would be small consolation to the victims in Japan and South Korea. The strong possibility that U.S. air strikes would lead to a disastrous wider war is the principal reason why even most hawks who cavalierly suggest that course with respect to Iran’s nuclear program rarely make the same proposal regarding North Korea.

The third option is to accept North Korea as a nuclear-weapons state and rely on deterrence to prevent aggressive behavior. There is a credible argument for that approach. After all, the United States has deterred other bad nuclear actors in the past, most notably the Soviet Union and Maoist China, and could probably deter the likes of Kim Jong-Il. But being able to deter an outright attack still leaves room for a great deal of dangerous North Korean mischief. Pyongyang’s proliferation activities are especially worrisome. If, as it appears, North Korea gave nuclear assistance to Syria, one must wonder what other countries — or even more troubling, nonstate actors — might also be beneficiaries of such assistance. Living with a nuclear-capable North Korea would be, at the very least, a nerve-wracking experience.

There is a final option that deserves more consideration. It would amount to inducing (bribing) China to remove Kim Jong-Il’s regime and install a much more pragmatic government in Pyongyang, along with the explicit objective of encouraging Korean reunification within the next generation. During my visit to China in late April, policymakers professed firm loyalty to Beijing’s long-time ally, but there was also a distinct undertone of exasperation with Pyongyang.

If the price were right, Chinese leaders might be bold enough to topple Kim with a palace coup. But the price would certainly not be cheap. At the very least, Beijing would want a commitment from the United States to end its military presence on the Korean Peninsula and, probably, to phase out its security alliance with South Korea. In all likelihood, Chinese leaders would also want U.S. concessions on the Taiwan issue: probably a prolonged suspension of, if not an end to, arms sales to Taipei.

Those would not be easy concessions for U.S. policy makers. But American leaders must ask themselves whether such sacrifices might be a necessary price to end the North Korean nuclear threat.

In any case, U.S. officials need to be thinking about a Plan B now. It is not a prudent strategy simply to hope that the six-party talks will produce an enforceable, effective solution. Given North Korea’s record, that is merely the triumph of hope over experience.