When he spoke before world leaders at United Nations headquarters earlier this month, President Barack Obama raised the stakes on nuclear negotiations with Iran, directing Secretary of State John Kerry to reach a “meaningful agreement” with Tehran. With a new round of talks between Iran, the United States and five other world powers set to resume in just weeks, it’s time to focus on what kind of agreement both sides can accept.

Negotiating this “win-win” deal on Iran’s controversial nuclear program won’t be easy or quick, but it’s possible if both sides are willing to be more flexible and transparent. And Iran’s new and more pragmatic president, Hassan Rouhani, is sending the right signals — as he did in a recent interview with NBC in which he said Iran has “never sought, nor will ever seek, nuclear weapons.”

The U.S. should put Iran’s encouraging words to the test by presenting a proposal that meets the international community’s most serious concerns about Iran’s nuclear program and guards against a nuclear armed Iran. A deal also must provide Tehran with the sanctions relief it needs for its economy and the conditional right to continue nuclear activities related to energy and the production of isotopes used for medical treatment.

Washington shouldn’t let the perfect be the enemy of the good as it considers a deal with Iran. Requiring Iran to give up all of its nuclear activities may have been possible a decade ago, before it began enriching uranium. But now, insisting that Iran commit to complete abandonment of its nuclear program, as some U.S. policymakers still demand, is naïve and unreasonable.

It’s time to be realistic about crafting a proposal allowing Iran to continue nuclear activities, including enrichment, but in a limited program and under more stringent international safeguards.

Reaching a deal that limits Iran’s enrichment is crucial and necessary, because Iran is unlikely to give up all of its enrichment activities — it has forfeited billions of dollars in oil revenues to build its nuclear program.

Rather, the United States should focus on securing verifiable restrictions on the most sensitive aspects of the nuclear program: limiting Iran’s stockpile of enriched uranium, capping the number of centrifuges that it operates, and increasing transparency and monitoring. With these restrictions in place, Iran would be unable to deviate from exclusively civilian nuclear power activities without the international community detecting its activities.

Pragmatic U.S. policymakers, such as former Secretary of State Hillary Rodham Clinton, understand this. Testifying before the House Foreign Affairs Committee in March 2011, Clinton said that in the future, having assured the international community that it isn’t seeking nuclear weapons and that it is committed to greater transparency, the United States should recognize a limited Iranian nuclear program.

A meaningful deal that addresses the most important concerns that Washington has about Iran’s nuclear program also needs to provide meaningful sanctions relief. Rouhani campaigned on revitalizing the economy — he will not be able to sell a package deal to the Iranian people that does not offer substantive sanctions relief.

Unfortunately, some members of Congress seem determined to torpedo a deal before negotiations have even begun by refusing to consider sanctions relief in exchange for nuclear concessions.

Congress also needs to realize that further sanctions at this time and the removal of presidential waiver authority will send the wrong signals to Iran and undercut our diplomats at the negotiating table. If Washington is talking about giving diplomacy a chance, while tightening the sanctions screws at the same time, Tehran is unlikely to trust that the United States is negotiating in good faith.

The departure of Mahmoud Ahmadinejad and arrival of Rouhani sets the stage for major progress on the Iran nuclear standoff. It’s time for the United States to give Rouhani a chance to follow up on his words with concrete actions that reassure the international community that Iran will not build nuclear weapons. And it’s time for Washington to demonstrate to Tehran that meaningful sanctions relief will be provided in exchange for limits to the nuclear program.

In short, it is time to stop talking about the perfect, impossible agreement and start talking about the kind of deal that is possible with real-world diplomacy and pragmatic way to secure U.S. interests.

Greg Thielmann is a senior fellow and Kelsey Davenport a nonproliferation analyst at the Arms Control Association.