Consider the following scenario. A Democratic U.S. administration, working closely with key international partners, negotiates a nuclear nonproliferation agreement with an adversarial rogue state. The deal, an imperfect compromise, would lessen the country’s international isolation and provide some economic benefit in exchange for eliminating the means to produce nuclear weapons.

A new Congress is then elected, whose Republican majority vociferously rejects “rewarding bad behavior” and opposes the deal. It bans the provision of economic assistance unless and until the regime abandons all its nuclear activities and changes its destabilizing behavior in the region. The deal then predictably falls apart, the tightening of U.S. sanctions fails to have the desired effect, the military option proves nonviable, and the rogue state moves forward with its nuclear program, ultimately testing and stockpiling a growing number of nuclear weapons.

The scenario I’m referring to is not Iran today but North Korea in 1994, when an “Agreed Framework” negotiated by the Clinton administration was sharply criticized by members of a new Congress who insisted on a “better deal.” They objected to the U.S. provision of fuel oil and light water power reactors for North Korea, which, while itself failing to fully implement the deal, eventually responded by withdrawing from the Nuclear Nonproliferation Treaty and becoming an overt nuclear weapons state.

Now there are many differences between Iran today and North Korea then, and it may well be that even the scrupulous implementation of the U.S. side of the agreement would not have prevented a North Korean nuclear weapon. Moreover, the comprehensive deal being negotiated between the P5+1 nuclear powers and Iran will be far more detailed and comprehensive, including in its verifications provisions, than the relatively loose, four-page Agreed Framework was. But the experience with North Korea does provide a potential lesson: In the messy world of nuclear nonproliferation, the perfect can be the enemy of the good. Insisting on a perfect deal could be a recipe for having no deal at all — with devastating consequences all around.

No one involved in the negotiation of the framework agreement with Iran, as I was from the time negotiations began until I left the Obama administration in April, believes it is an ideal solution. Critics are right that Iran has the nuclear infrastructure it has today only by violating its international obligations and lying to the world about its capabilities and intentions. In an ideal world, therefore, a nuclear agreement with Iran would eliminate its nuclear infrastructure and stockpile of low enriched uranium, provide for “anywhere, anytime” inspections, require Tehran to admit past nuclear weapons work, and — as proposed in various amendments to the Iran legislation Congress considered last week — require Iran to recognize Israel and cease its support for terrorism in the region and beyond.

But we do not live in a perfect world, and the “better deal” proposed by the critics of the Lausanne framework is a fantasy. During 10 years of increased pressure from 2003 to 2013, while the U.S. and the world insisted that Iran abandon all enrichment, Iran vastly increased its nuclear infrastructure and knowledge, building thousands of new centrifuges, conducting extensive research and development on advanced models, accumulating stockpiles of enriched uranium, commencing construction of a heavy-water reactor capable of producing weapons-grade plutonium and building an underground enrichment facility out of reach of international inspectors.

Even assuming other world powers could somehow be persuaded to increase sanctions on Iran today if Congress votes against a comprehensive agreement, it requires an even bigger leap of faith to believe Iran would respond by giving in across the board. The more likely outcome is that we would find ourselves back at the table in another year or two, facing an Iran with an even more advanced nuclear program and even less willing to accept a workable compromise. The alternative would be military force and all the drawbacks that option entails — including that Iran would likely emerge even more determined to produce nuclear weapons, requiring us to use force again in the not-too-distant future.

The Lausanne arrangement is not perfect, but it is far better than any realistic alternative, and much more comprehensive than the North Korea framework. Through significant reductions in Iran’s nuclear infrastructure, constraints on its R&D and unprecedented verification mechanisms, it would extend the time needed for Iran to produce enough nuclear material for a bomb from just a few months to more than a year, until at least 2025. And even after some of the constraints on Iran’s infrastructure are lifted, a comprehensive inspections regime will remain in place, and all the options open to us now to prevent Iran from acquiring a nuclear weapon will be open to us then. Rejecting the opportunity to constrain Iran’s nuclear program in this way based on the hope that down the road Iran will agree to a better deal, or that the military option provides an effective alternative to it, is a luxury outside actors may possess, but it would be an enormous gamble for the president of the United States.

There are differences between Iran now and North Korea then that may actually play in our favor. Iran’s leadership is arguably more rational and susceptible to public pressure to improve the economy, our military option is more credible this time because Iran cannot destroy a nearby capital with artillery as Pyongyang can destroy Seoul, and Iran does not yet have enough nuclear material for a weapon, whereas North Korea probably did. Congress should keep these differences in mind as it considers whether to support a nuclear deal with Iran. But it should also keep in mind an important potential lesson from the previous experience: Rejecting an imperfect deal can result in no deal at all. And no deal at all, in the most relevant recent case, resulted in a new, and very dangerous, nuclear weapons state.
This article was written by Philip Gordon for Politico on May 11, 2015. Philip Gordon is a senior fellow at the Council on Foreign Relations. From 2013 to 2015, he was special assistant to the president and White House coordinator for the Middle East, North Africa and the Gulf Region.