In a recent Foreign Affairs article, “Lessons from North Korea,” John Delury urged diplomats to heed those lessons in implementing the nuclear agreement with Iran. Based on the U.S. experience with the 1994 Agreed Framework with North Korea, Delury argued persuasively that the nuclear accord with Iran must be followed by the construction of a fundamentally new Iranian relationship with the United States, the region, and the world.

Another lesson from North Korean negotiations is equally important: that the United States must follow through on the commitments it makes during the negotiating process. In the case of the Agreed Framework, for example, the United States committed to reduce trade and investment barriers for North Korea within three months, to work a normalization of relations, and to permit the North Korean regime to build two light water reactors, the first to be completed in 2003. The United States took no meaningful action on its commitments for six years, and the foundation of the first reactor was not poured until August 2002, about eight years after the framework was agreed upon.

As Delury correctly notes, the incoming administration of former U.S. President George W. Bush opposed the Agreed Framework and walked away from the deal; some may thus conclude that the United States’ failure to fulfill its commitments did not matter. In fact, it had a significant impact on North Korea, which demonstrated considerable patience at the time.

In his State of the Union address on January 29, 2002, Bush anointed North Korea, along with Iran and Iraq, as a charter member of an “axis of evil.” Consistent with Vice President Dick Cheney’s statement that “We don’t negotiate with evil, we defeat it,” the Bush administration, for the remainder of its first term, conditioned its willingness to negotiate with North Korea on the “complete, verifiable, irreversible dismantlement” of its nuclear program. In other words, Washington began negotiations with an ultimatum, leaving very little room in the process for true dialogue. This gave North Korea less incentive to come to the bargaining table—harsh rhetoric and inflexible demands would limit the regime’s ability to find a mutually agreeable outcome.

The United States continued to reject overtures from North Korea; instead, Washington watched while Pyongyang produced plutonium for several weapons and developed its uranium enrichment facility. On February 10, 2005, North Korea announced that it had produced nuclear weapons, apparently capturing the administration’s attention. In a complete turnaround, the Bush administration agreed to a Statement of Principles in September of that year, which included provisions for “coordinated steps … in a phased manner in line with the principle of ‘commitment for commitment, action for action,’ ” a position consistent with more traditional diplomacy.

Members of the Comprehensive Nuclear-Test-Ban Treaty Organization's Eminent Persons Group are briefed by South Korean Army Sgt. Kwan Byung-hoon (2nd R) inside the U.N. Command Military Armistice Commission meeting room at the truce village of Panmunjom, which separates North and South Korea, in Paju, South Korea, June 26, 2015. Ahn Young-joon / Reuters The milestone Statement of Principles reaffirmed the goal of the six-party talks as the “verifiable denuclearization of the Korean Peninsula.” In it, North Korea committed “to abandoning all nuclear weapons and existing nuclear programs” and returning to the Nuclear Non-Proliferation Treaty, which included safeguards of the North Korean nuclear program administered by the International Atomic Energy Agency (IAEA). In addition, the six parties agreed to “promote economic cooperation … bilaterally and/or multilaterally,” and the United States and North Korea agreed to “respect each other’s sovereignty.”

Yet almost simultaneously, the United States took action to freeze about $25 million of North Korean funds deposited in a bank in Macau, in clear violation of its commitment to economic cooperation. The move was understandably interpreted by North Korea as a hostile act inconsistent with respecting its sovereignty, leading Pyongyang to suspend its participation in the next round of the six-party talks pending release of its funds. Tensions rose in 2006 with an exchange of threats between the United States and North Korea, and the Bush administration refused to engage in direct talks proposed by Pyongyang. On July 5, North Korea conducted a failed test of a long-range missile. The United States then tightened financial sanctions on North Korea and urged other nations to be wary of doing business with it. On October 9, 2006, North Korea conducted an underground test of a very low-yield nuclear device.

This advancement in North Korea’s nuclear ambitions prompted the United States to reevaluate the need for dialogue, and it decided to be more forthcoming. Although pro-forma six-party talks resumed from a 15-month hiatus in December, progress continued to flounder on the frozen funds issue, which would not be resolved until 2007, when the United States released the money as promised. Ultimately, this economic action accomplished nothing more than delaying the negotiations for almost two years during a critical moment, and allowed North Korea to conduct a nuclear test in the interim.

With impediments to negotiation now reduced, North Korea committed to shut down, disable, and abandon its nuclear weapons program, admit IAEA inspectors, and declare its nuclear program activities in return for one million tons of fuel oil and commitments to begin removing North Korea from the U.S. list of State Sponsors of Terrorism, as well as the termination of the Trading with the Enemy Act’s applicability to North Korea. By October 3, 2007, North Korea agreed to disable its Yongbyon nuclear facilities, to stop transferring nuclear materials or technology abroad, and to disclose the details of its plutonium program. On the other end, the United States made minimal commitments: advance the process of terminating sanctions under the Trading with the Enemy Act and begin removing North Korea from the list of State Sponsors of Terrorism.

A Taepodong-2 rocket is launched from the North Korean rocket launch facility in Musudan Ri April 5, 2009 in this picture released by the North's official news agency KCNA on April 8, 2009. KCNA / Reuters Only a little more than two months later, former U.S. Secretary of State Condoleezza Rice telegraphed a walk back from “commitment for commitment, action for action” by telling the Associated Press that the United States was not prepared to engage broadly with North Korea until “all aspects of its nuclear weapons program are ended first and foremost.” This implied a return to “complete, verifiable, irreversible dismantlement” of the North Korean nuclear program as a precondition to further negotiations. Less than a month later, North Korea accused the other five parties of the six-party talks of falling behind in their commitments, including delivery of fuel oil; as a result, it threatened to slow down the disablement of its nuclear facilities.

Nevertheless, North Korea proceeded to comply with its Phase II commitments to disable its reactor and report on its nuclear activities. On May 8, 2008, North Korea submitted extensive documentation of its nuclear reactor and reprocessing facility’s operations and gave China a detailed declaration of its nuclear programs that following June. On June 27, North Korea dramatically destroyed the cooling tower on its Yongbyon reactor.

After these major steps were taken, the United States again sought to change the conditions of its deal by introducing new stipulations. Although Phase II did not call for the verification of the North Korean declarations, Rice declared in June 2008 that the United States was moving up “issues that were to be taken up in phase three, like verification … into phase two” as a precondition to fulfilling its Phase II commitments. “Before these actions go into effect,” she said, “we would assess the level of North Korean cooperation in helping verify the accuracy and completeness of the declaration” of its plutonium program. North Korea emphasized in a statement on August 26, 2008 that a verification protocol was not included in the Phase II agreement. Nevertheless, Washington stood by its unwillingness to fulfill its Phase II commitments until extensive verification demands were accomplished. When the United States refused to budge from this position, North Korea withdrew from the six-party process in April 2009, threatened to bolster its nuclear deterrent, and ejected the IAEA and U.S. monitors from its nuclear sites. On May 25, 2009, North Korea conducted its second, and more successful, nuclear test.

There is no way to know whether the United States could have realized a nuclear-free Korean Peninsula by fulfilling its Phase II commitments. It is clear, however, that meaningful progress had been made. For example, ten of the 12 procedures for disabling the Yongbyon reactor had been completed by August 2008, and it has taken North Korea many years to repair it.

Implementation of the 2005 Statement of Principles was probably the last feasible opportunity to preclude a North Korean nuclear arsenal. Even if North Korea had decided to withdraw from the six-party talks, it was imprudent for the United States to provide it with a plausible reason for doing so. It would be advisable for Washington to comply with U.S. commitments in the Joint Comprehensive Plan of Action with Iran. After all, agreements last only when all parties involved fulfill their obligations. If the United States is willing to uphold its end of the bargain, there may be long-term success with the Iranian nuclear deal.