Despite the apparent failure of the “reset button” for U.S.-Russian relations, the nuclear arms agreement signed by Obama and Medvedev will significantly reduce each country’s respective nuclear weapons arsenals and strengthen U.S.-led efforts to address a far more pressing issue: Iran’s continuing uranium enrichment and the concomitant threat of nuclear proliferation in the Middle East.

Of course, as many analysts have noted, Obama and his Russian counterparts said little publicly about Iran, reflecting deep divisions as well as a desire for renewed cooperation on less controversial challenges. While Obama reportedly stressed the danger of Iran’s nuclear ambitions repeatedly in private meetings with Medvedev and Putin, believed by many to still be holding the reins, there should be little optimism about the prospect of overt Russian assistance with the Iranian nuclear threat.

Indeed, as Paul Richter writes in the Los Angeles Times, Russia remains a major impediment to imposing effective international pressure on Iran:

Russia’s long-standing economic relationship with Iran has been a principal hurdle to American efforts to curb Tehran’s nuclear ambitions.

Although the West believes tough sanctions by Moscow would play a decisive role, Russia has continued to balk. At their news conference, Obama cited the threat of Iran obtaining nuclear weapons, but Medvedev remained silent, refraining from even mentioning Iran by name.

However, other accounts hinted at future cooperation on nuclear proliferation. Clifford Levy and Peter Baker in the New York Times:

But after hours of meetings at the Kremlin, the presidents agreed to conduct a joint assessment of any Iranian threat and presented a united front against the spread of nuclear weapons.

Mr. Obama hailed the arms agreement as an example for the world as he pursued a broader agenda aimed at countering — and eventually eliminating — the spread of nuclear weapons, a goal he hopes to make a defining legacy of his presidency.

While the United States and Russia together have 95 percent of the world’s nuclear weapons, Mr. Obama also views Russia as an influential player in deterring nuclear programs in Iran and North Korea.

“This is an urgent issue, and one in which the United States and Russia have to take leadership,” Mr. Obama said. “It is very difficult for us to exert that leadership unless we are showing ourselves willing to deal with our own nuclear stockpiles in a more rational way.”

Mr. Medvedev expressed willingness to help fight the proliferation of nuclear weapons in places like Iran and North Korea. “It’s our common, joint responsibility, and we should do our utmost to prevent any negative trends there, and we are ready to do that,” Mr. Medvedev said.

Similarly, in his speech on Tuesday to the New Economic School in Moscow, Obama declared:

That’s why America is committed to stopping nuclear proliferation, and ultimately seeking a world without nuclear weapons. That is consistent with our commitment under the Nuclear Non-Proliferation Treaty. That is our responsibility as the world’s two leading nuclear powers. And while I know this goal won’t be met soon, pursuing it provides the legal and moral foundation to prevent the proliferation and eventual use of nuclear weapons.

[…]

As we keep our own commitments, we must hold other nations accountable for theirs. Whether America or Russia, neither of us would benefit from a nuclear arms race in East Asia or the Middle East. That’s why we should be united in opposing North Korea’s efforts to become a nuclear power, and opposing Iran’s efforts to acquire a nuclear weapon. And I’m pleased that President Medvedev and I agreed upon a joint threat assessment of the ballistic challenges — ballistic missile challenges of the 21st century, including from Iran and North Korea.

This is not about singling out individual nations — it’s about the responsibilities of all nations. If we fail to stand together, then the NPT and the Security Council will lose credibility, and international law will give way to the law of the jungle. And that benefits no one. As I said in Prague, rules must be binding, violations must be punished, and words must mean something.

While the widespread pessimism regarding a new beginning for U.S.-Russian relations is understandable – though the idea that years of mistrust could be “reset” after a two day visit ought to be treated with skepticism –  the resumption of substantive nonproliferation efforts will demonstrably strengthen U.S. efforts to bolster international resolve to deter Iran from building a nuclear weapon, or ultimately in containing a nuclear or near-nuclear Iran. That Obama speaks of one day eliminating nuclear weapons, an issue he first addressed while a university student, grants legitimacy and moral purpose to the U.S. as it seeks to guide European and international allies.

More importantly, the agreement announced Tuesday will reduce the number of nuclear weapons, which, given their tremendous destructive capacity, represent an inherent global threat. In an age where stateless actors such as Al Qaeda seek nuclear weapons or at least some type of nuclear material, and as the expansive Russian nuclear arsenal atrophies amid economic decline, the disposal and securitization of nuclear material is of paramount importance.

As the U.S. continues to engage Iran despite the post-election crackdown and as a power struggle moves from the streets to the highest circles of Iran’s governing theocracy, nonproliferation efforts such as those pursued by the Obama administration will allow the U.S. to present a more compelling case to the international community as it gathers support for a common effort to confront the rising threat emanating from Iran’s growing quantity of enriched uranium.

Brendan Boundy is an intern with the New Atlanticist.  He is pursuing a master’s degree from The Fletcher School of Law and Diplomacy at Tufts University.