This article originally appeared at Brookings.

April 5 marks the 10th anniversary of the speech in which Barack Obama laid out his vision for a world without nuclear weapons. It did not gain traction. Instead, the United States and Russia are developing new nuclear capabilities, while the nuclear arms control regime is on course to expire in 2021. The result will be a world that is less stable, less secure, and less predictable.

A WORTHWHILE VISION

Just 10 weeks after his inauguration, President Obama’s first trip to Europe took him to Prague. Speaking in Hradcany Square, Obama voiced his deep interest in reducing nuclear arms, including a “commitment to seek the peace and security of a world without nuclear weapons.” He added that reaching that goal would require time, and that, as long as nuclear arms existed, the United States would maintain a “safe, secure and effective” nuclear arsenal.

Obama’s critics mocked him as naïve and idealistic. Achieving a world without nuclear arms would require, at a minimum, that nations conclude that they could protect their vital interests without nuclear arms; that new and very intrusive verification mechanisms were developed and agreed; and that an enforcement mechanism against any cheating state have real teeth—daunting challenges, to be sure. That said, a world in which nuclear arms were reliably and verifiably eliminated would be very much in the U.S. interest.

Nuclear war today poses the one existential threat to the United States. In a non-nuclear world, America would enjoy the advantages of geography (the protection afforded by two wide oceans and friendly neighbors in Canada and Mexico), the world’s most powerful conventional forces, and an unrivaled network of allies. Deterrence would not end; U.S. conventional forces could threaten enormous costs to any would-be adversary menacing America or its allies.

A big problem arises, however, in trying to persuade other states to accept a non-nuclear world. The balance of advantages and disadvantages that would make such a world so attractive for the United States would seem very different to other countries, such as Russia.

EVENTS TOOK A DIFFERENT COURSE

In any event, matters took a different course than Obama had hoped. Following signature of the New Strategic Arms Reduction Treaty (New START) in April 2010, he called for negotiations with Russia to further reduce strategic nuclear weapons and bring in non-strategic nuclear weapons. That raised the possibility that, for the first time ever, the two countries might negotiate limits on their entire nuclear arsenals.

Moscow chose not to engage in further bilateral negotiations—in part because Washington proved unready to discuss limits on missile defense or conventional strike systems. The Russians also sought a multilateral negotiation, though they have never offered a proposal or explained how one treaty could limit forces as disparate as those of the United States and Russia (4000 to 4500 nuclear weapons each) and China and France (less than 300 each). A Washington Naval Treaty-type agreement assigning unequal limits to its adherents presumably would be unwelcome in Beijing, Paris, and other capitals. 

Today, Russia and the United States have launched major nuclear force modernization programs. These programs focus largely on replacing old systems. Weapons systems age out and need replacement. Both sides, however, also plan to add new capabilities, including exotic strategic weapons and low-yield nuclear arms. One likely and unfortunate result: The threshold for employment of nuclear weapons will be lower.

While U.S. and Russian nuclear modernization proceeds, the regime that limits U.S. and Russian nuclear arms has begun to break down. Russia violated the 1987 Intermediate-range Nuclear Forces (INF) Treaty by deploying a prohibited cruise missile. Neither the Obama nor the Trump administration came up with an effective strategy to bring Moscow back into compliance, and it appears that President Trump barely tried, perhaps reflecting the influence of National Security Advisor John Bolton, who has long expressed skepticism about any agreements that constrain U.S. military forces. The INF Treaty will expire this August when the United States withdraws.

The end of the INF Treaty will leave New START, which caps the sides’ strategic missiles and bombers as well as their deployed strategic warheads, as the sole remaining nuclear arms control agreement. Unlike the INF Treaty, both sides have complied with New START’s limits, but it has less than two years to run before it expires.

New START’s terms allow for an extension of up to five years. Moscow historically has wanted some bounds on U.S. strategic forces. The Russians broached the idea of extension in early 2017 and have raised it several times since then. Extension should be a no-brainer for Washington: It would cap Russian strategic forces until 2026 while forcing no change in U.S. modernization plans, since the Pentagon designed those plans to fit within New START. Extension would also continue the flow of information that the United States receives about Russian strategic forces from New START’s verification measures. Unfortunately, Trump’s grasp of these questions appears weak, and Bolton does not appear a fan of New START.

AN UNCERTAIN FUTURE

The two nuclear superpowers thus will likely find themselves in 2021 in a situation that they have not faced for decades—a world with no constraints on nuclear force numbers. For the United States, that world will prove less stable and less secure as new nuclear capabilities undermine the strategic balance and threaten America. It will prove less predictable, as the data exchanges, notifications, and on-site inspections provided by New START cease. And it will almost certainly prove more costly, as the Pentagon has to make worst-case assumptions.

True, achieving Obama’s vision of a world without nuclear weapons now seems unrealistic. But we could use some presidential commitment to controlling those weapons.