After tumultuous negotiations, the six-party talks reached agreement on a deal that would end North Korea's nuclear-weapons program and end the country's international isolation. The agreement took three and a half years to conclude, during which the North exploded a nuclear weapon. There is no guarantee that the deal will be implemented; history provides little grounds for optimism. But this week's agreement is an important first step, and all nations must work hard to ensure that all the commitments are honored.

The six-party talks have been fitful. There were high hopes in September 2005 when the fourth round of talks produced a declaration that identified basic principles for a deal. The Sept. 19 Joint Statement stipulated that the six parties should take coordinated steps to implement their agreement in a phased manner and in line with the principle of "commitment for commitment, action for action." Yet the very day after the declaration was released, North Korea and the United States showed deep disagreement about the terms of that agreement, its requirements and the process by which it would unfold.

That divide was complicated by the imposition of financial sanctions by the U.S. on North Korean companies accused of involvement in the proliferation of weapons of mass destruction and their means of delivery and money laundering and counterfeiting of U.S. currency. For Pyongyang, those steps confirmed "the hostile policy of the U.S." toward North Korea and its view that Washington was not negotiating in good faith. North Korea insisted that the sanctions had to be lifted before the six-party talks could resume, and demanded direct bilateral talks with the U.S. Washington argued the issues were separate, but it was prepared to address them within the context of the six-party talks.