Talks between Iran and the five permanent members of the U.N. Security Council plus Germany resume again this weekend, with Tehran giving hints that it may take a more constructive attitude to negotiations than it did during the previous round in 2011. Iranian nuclear officials have suggested that Iran might curtail its 20 percent uranium enrichment program, which would meet almost halfway the expected demands of the United States and its so-called P5+1 negotiating partners.

The United States and its allies reportedly plan to demand the immediate cessation of uranium enrichment to 20 percent, and a closure of the hardened Fordow enrichment plant, possibly in exchange for promises of no further sanctions. If the United States and its international partners are able to achieve these objectives, they will significantly slow Iran's progress toward having the capacity to produce a nuclear weapon, score a victory for the two-track policy of diplomacy and economic pressure, and provide a template for more fully resolving outstanding issues surrounding Iran's nuclear program in future talks.

Will that happen? Predicting the future is a fool's game, but it's important to recognize that the United States and its partners are going into talks with Iran this weekend in a position of strength that would have been hard to imagine four short years ago. This is in large part thanks to the Obama administration's hard diplomatic work rebuilding alliances and, importantly, its demonstrated willingness to engage in good faith with the Iranian regime.

Far from being a naïve move, as some have charged, President Obama's outreach to Iran at the outset of his administration served an important purpose. By revealing Iran as the recalcitrant party, his administration has been able to forge a far stronger and more enduring international coalition to pressure Iran. Instead of "validating the mullahs," as one critic alleged, Obama's engagement effort has in fact further isolated them.

Some observers argue that such a deal will not be enough, suggesting that Iran must agree to effectively dismantle its entire nuclear program as the result of any deal. Anything less means the "unprecedented leverage" now at American disposal will have been "squandered."

But rather than repeating the mistakes of the recent past, overplaying our hand, demanding complete Iranian capitulation, and achieving nothing, the U.S. and its partners should maintain their advantage by offering Iran an opportunity to demonstrate its own good faith with a set of steps that it can plausibly present as a win. While the long-term goal remains an Iranian nuclear program fully under the monitoring of the International Atomic Energy Agency, the near-term goal should be to continue to lengthen Iran's nuclear timeline while trying to build a combination of carrot and sticks to achieve the more comprehensive deal in the future. This isn't "squandering" leverage; it's making sure the United States and its partners preserve the significant leverage they now have to secure immediate and long-term objectives.

There have been other recent indications that Iran's leaders could be in a more accommodating mood. In February, in what could be seen as an attempt to allay international concerns over Iran's possible desire for weaponization of its enriched uranium, Iran's Supreme Leader, Ayatollah Ali Khamenei, stated that having nuclear weapons "is a sin as well as useless, harmful and dangerous." On March 8, Khamenei praised President Obama's remarks downplaying the talk of war, declaring a "window of opportunity" for diplomacy with Iran. And in a recent interview with CNN, published on March 16, Mohammad Javad Larijani, a close adviser to Khamenei, disavowed Iranian President Mahmoud Ahmadinejad's notorious remark that Israel would be "wiped off the map," saying that Ahmadinejad's comment was "definitely not" meant in a military sense and that such a move was not "a policy of Iran."

In a recently published interview, former Iranian president Ali Hashemi Rafsanjani, who was recently re-appointed by Khamenei as head of Iran's Expediency Council, clarified a 1999 statement about Israel's vulnerability in a nuclear-armed Middle East, saying it was mistakenly interpreted as a threat against Israel. "Having nuclear weapons is not even in Israel's interest," Rafsanjani explained. "We deeply believe that nuclear weapons must not exist, and this has been part of our policy."

While we should be careful about taking at face value these signals out of Tehran, taken together they may represent an effort by key Iranian leaders to address issues of concern to P5+1 negotiators -- Iran's potential efforts to develop a nuclear weapon, and the threat that such a weapon could pose to other countries in the region, particularly Israel.

We should not, of course, be in the practice of rewarding countries for simply ceasing to threaten other countries with destruction. But we should recognize that for a regime that thrives on defiance and hostility toward the United States and Israel, these recent statements out of Iran represent an attempt to lower the temperature.

President Obama's reported response to Khamenei -- we appreciate your statement against nuclear weapons, now show us you're serious -- is appropriate. The United States and its partners have, through skillful and painstaking diplomacy, generated considerable leverage over Iran. Rather than squandering this leverage by simply pushing Iran to surrender and most likely achieving nothing, they should work to maintain the stock of leverage while offering Iran opportunities to make good on its own recent statements.

An all-or-nothing approach to the Iranian nuclear question is unlikely to yield positive results for the United States and its partners. Sacrificing progress on areas of great concern in pursuit of maximalist goals is an irrational approach for the United States to take.

Saying yes to a deal that brings an IAEA-certified halt to Iran's 20 percent enrichment and halts progress at Fordow in exchange for holding off further sanctions does not foreclose further scrutiny of Iran's nuclear program or let Tehran off the hook. On the contrary, it has the potential to strengthen those efforts by allowing Iran to prove its seriousness. And it allows the international community to show the paranoid regime in Tehran that it will live up to its commitments if Iran lives up to its own. The likelihood of immediate major breakthroughs in this weekend's talks is low, but success would be the start of a gradual, step-by-step process of negotiations that achieves U.S. goals.

Matthew Duss is a policy analyst at the Center for American Progress, a non-partisan think tank based in Washington, DC.