It's hard for most people to imagine that the Iraq war has had anything but a negative impact on the world's efforts to stop the spread of mass destruction weapons. After all, this was the first war ever fought—at least ostensibly—to counter the spread of such weapons and none have actually been found. Nevertheless, the U.S.-led invasion of Iraq is having one unexpected benefit: It has incited the war's opponents to seek out effective ways, short of force, to stem the spread of these weapons. The result has been progress on several key initiatives—from seizing illicit cargo on the high seas, to negotiating with rogue regimes, to action at the United Nations.

The first example of this new activism came when France and Germany, two of the war's most virulent critics, set aside their disagreements over Iraq and signed on to the Bush administration's new Proliferation Security Initiative. France and Germany joined in May 2003; Russia, another key opponent of the war, joined earlier this month. The initiative aims to interdict ships suspected of carrying weapon-related goods on the high seas. The doubtful legitimacy of this step under international law makes the participation of the Europeans all the more surprising. But volunteering to participate in PSI has allowed these states to show their cooperative side. And joint training operations along with some high-profile successes—like the October 2003 seizure of the BBC China bound for Libya with centrifuge parts—have helped mitigate tensions caused by the diplomatic fall-out surrounding the war.

The Iranian nuclear crisis, which came to a boil last fall, also gave U.S. allies who opposed the war an opportunity to flex their leadership muscles on proliferation. France and Germany, along with Britain, undertook negotiations with Iran in the wake of revelations that it had run a secret nuclear program for nearly two decades. The Europeans convinced Iran to freeze its uranium enrichment effort and to accept enhanced inspections of its nuclear infrastructure. While Iran's adherence to this pledge has been less than complete, the Europeans have kept the pressure on: they issued a joint condemnation of Iran's behavior and have worked hard to make Iran comply with its obligations to the International Atomic Energy Agency. In the meantime, the European Union has been willing to suspend lucrative trade negotiations with Iran until all nuclear questions are cleared up. This is a powerful arm-twisting mechanism unavailable to the United States—and the Europeans have been willing to use it.

The Iraq war also appears to have convinced the Chinese that without taking a more active role in negotiating with North Korea, there might be a military confrontation on the Korean peninsula. The possibility of war on its borders led China to set in motion the "six party process," a series of talks that also include Japan, North Korea, Russia, South Korea and the United States. This renewed effort from China, beginning in April 2003, came on the heels of the Iraq war and reversed China's long-held policy of remaining aloof.

Finally, a number of U.S.-sponsored nonproliferation initiatives have garnered unexpected support from erstwhile opponents of the Iraq war. This April, in the U.N. Security Council, members like France, Germany, Pakistan and Russia supported a sweeping resolution on nonproliferation introduced by the United States. The resolution seeks to deny all national territories to illicit bomb makers by criminalizing proliferation and requiring states to enact effective export controls. What’s more, the resolution was offered under Chapter VII of the U.N. Charter, meaning sanctions and even force could be authorized for noncompliance.

And earlier this month at the G-8 summit in Sea Island, Georgia, leaders from France, Germany and Russia put festering disagreements with the United States over Iraq aside and threw their support behind a plan, first set out by President Bush, to reform nonproliferation rules. The plan aims to prevent nuclear materials and technology from being used for weapon purposes by suspending exports of sensitive nuclear equipment for one year. It also targets states that violate their nonproliferation obligations, and singles out Iran and North Korea as particular challenges.

What all these examples suggest is that in the wake of the Iraq war, foreign leaders are especially eager to prove their nonproliferation mettle. European leaders have rushed to demonstrate that alternatives to the use of force exist; the Chinese have realized that war over weapons is possible and have negotiated to make it less likely; and most states have worked harder to strengthen existing rules against proliferation and to create new mechanisms to supplement them. However unexpected, the Iraq war has helped inspire this shift. That’s a welcome bit of good news from an event that has otherwise engendered far more setbacks than successes.