Just a few weeks ago, expectations ran high in both the United States and East Asia that the agreement reached last year to terminate North Korea’s nuclear program was on the brink of fulfillment. Pyongyang had pledged to permanently disable its nuclear facilities at Yongbyon and give an accounting of its entire nuclear program by December 31, 2007.

But the North Korean regime failed to meet that deadline. Perhaps even worse, North Korean officials now insist that a sketchy declaration given to the other nations in the six-party talks in November was sufficient to fulfill its obligation to disclose all of the country’s nuclear activities.

That position is manifestly absurd. A full accounting would require details about the amount of plutonium extracted from the Yongbyon reactor, the number and location of any nuclear weapons that have been manufactured, and the status of the parallel uranium enrichment program that U.S. intelligence agencies believe North Korea has been pursuing for years. The November statement does none of that. It comes nowhere close to meeting the U.S. goal of securing a complete, verifiable and irreversible end to Pyongyang’s nuclear program.

This latest round of duplicity on the part of the North Korean regime should come as no surprise to those who have monitored Pyongyang’s conduct over the years. North Korea has reneged on every agreement it has ever made regarding nuclear matters. It signed the Nuclear Non-proliferation Treaty in the 1980s and concluded a bilateral agreement in 1992 with South Korea to keep the Peninsula nuclear free. Yet, it was caught almost immediately pursuing a weapons-development program in violation of both commitments. Pyongyang then signed an agreement with the United States in 1994 to freeze its illicit program in exchange for energy assistance and other concessions. That agreement broke down in late 2002, when U.S. intelligence agencies discovered that North Korea was pursuing a separate uranium-enrichment program.

Washington’s reaction to Pyongyang’s latest broken promise has been surprisingly mild. On January 9, America’s envoy to the six-party talks, Assistant Secretary of State Christopher Hill, stressed that there was “no need to panic” over the missed deadline. He expressed confidence that North Korea would ultimately provide the required information.

Perhaps. But given the track record of the North Korean regime, it would not be wise to make a large wager on that outcome.

It is possible that the North Koreans are merely engaging in bargaining tactics to obtain larger quantities of energy and financial aid than have already been promised, and if they gain further concessions, they will eventually make a full disclosure. But American and east Asian leaders also need to consider another possibility — that Pyongyang is merely stalling while it continues to build nuclear weapons from the plutonium it has already extracted from the Yongbyon reactor. For all of its promises to the contrary, North Korea may be determined to crash the global nuclear weapons party.

One need not go so far as John Bolton, former U.S. ambassador to the United Nations, who has charged that the Bush Administration is guilty of a feckless appeasement policy toward Pyongyang. And one certainly should not entertain the suggestion of Bolton and other hawks that Washington explicitly put the military option back on the table regarding North Korea’s nuclear program. To risk igniting a full-scale war on the Korean Peninsula would make an already bad situation infinitely worse.

At the same time, U.S. officials must stop letting hope triumph over experience when it comes to dealing with North Korea on the nuclear issue. Those officials also need to consider a fall-back plan if the six-party talks fail to produce an effective and worthwhile solution. Relying on deterrence supplemented by a regional missile defense program may be the most feasible option. Another possibility is to induce China to remove the current ruling elite in its troublesome client state and replace it with a more pliable regime, in exchange for a U.S. promise to end its military presence on the peninsula.

There may be other policy options as well. The crucial point is that U.S. leaders need to be considering alternative strategies now, rather than investing all hope in a diplomatic solution that looks increasingly shaky.