An unarmed Minuteman III intercontinental ballistic missile launches during an operational test at Vandenberg Space Force Base, California, Wednesday, May 21, 2025. (U.S. Air Force photo by Airman 1st Class Jack Rodriguez Escamilla) Why Nuclear Disarmament Collapsed – and Why Deterrence Must Guide the Future

When the Cold War ended, it seemed as though nuclear arms control had reached its natural high point. The Soviet Union had dissolved, the Warsaw Pact disappeared, and Washington and Moscow negotiated a succession of bilateral agreements—START I, START II, the 2002 Treaty of Moscow, and eventually New START—that placed both nations on what appeared to be a steady path toward deep reductions.

There was a widespread belief, especially in Western capitals, that the era of large-scale nuclear arsenals was ending.

Three decades later, that optimism looks misplaced. Nuclear arsenals are expanding, not contracting. Revisionist powers are more assertive, not less. Security guarantees that once underpinned global nonproliferation are now under strain. And the largest land war in Europe since 1945 has reinforced a hard truth many preferred to ignore: nuclear weapons continue to shape the world’s most consequential decisions.

What went wrong? And why did an international movement that once seemed ascendant—embodied by sweeping visions such as the Treaty on the Prohibition of Nuclear Weapons—collapse so completely?

The answer lies in a series of profound geopolitical misjudgments, strategic shocks, and technological disruptions that reshaped the global nuclear landscape. The path to disarmament did not fail because of a lack of moral conviction; it failed because the world moved in the opposite direction.

Today, the task for Washington and its allies is not the pursuit of grand nuclear abolition schemes, but the more urgent and difficult work of strengthening deterrence, stabilizing security guarantees, and erecting guardrails in an increasingly dangerous nuclear era.

The Geopolitical Mirage

Anyone who lived through 1989 remembers the optimism that followed the fall of the Berlin Wall. Western policymakers, scholars, and commentators embraced the view that authoritarian governments would liberalize and integrate into a rules-based international order. History, it seemed, had an arrow—and it pointed toward democracy.

In retrospect, this assumption was profoundly mistaken.

As my colleague Tom Wright has argued, Western leaders projected their hopes onto geopolitical adversaries, believing that globalization would gradually pull Russia, China, and other authoritarian states into the orbit of the liberal order. Instead, as Tom noted, Russia and China eventually came to see the so-called liberal international order as an existential threat to their regimes and began to push back hard.

The result is the world we face today: powerful, revisionist states with growing nuclear arsenals, increasingly confident leaderships, and a demonstrated willingness to test the boundaries of the post–Cold War order.

The Revolution in Military Affairs—and Its Consequences

If geopolitics created the conditions for disillusionment, technology provided the catalyst.

America’s overwhelming victory in the 1991 Gulf War—featuring precision-guided munitions, stealth aircraft, real-time command and control, and space-enabled targeting—ushered in what became known as the Revolution in Military Affairs (RMA). The old Soviet concept of the “reconnaissance-strike complex” had arrived in devastating fashion.

The demonstration had a profound effect on foreign militaries.

As India’s former Army Chief put it shortly after the war: “If you want to take on the United States, you need nuclear weapons.”

Russia, China, North Korea, and other authoritarian states drew the same conclusion. Even with weak economies—and, in North Korea’s case, famine—they invested heavily in nuclear capabilities as an insurance policy against overwhelming U.S. conventional power. For these regimes, nuclear weapons were not Cold War relics; they were survival tools.

While many in the West celebrated a supposed “end of history,” others were preparing for its next chapter.

The Age of Unrealistic Expectations

Western democracies also contributed to the disarmament illusion. Two events were critical:

The 2007 Wall Street Journal op-ed by Henry Kissinger, George Shultz, William Perry, and Sam Nunn calling for a world free of nuclear weapons.

President Barack Obama’s 2009 Prague speech envisioning “the peace and security of a world without nuclear weapons.”

These statements galvanized movements such as Global Zero and gave political momentum to ambitious projects like the Treaty on the Prohibition of Nuclear Weapons. But they also created expectations divorced from geopolitical reality.

By the end of Obama’s presidency, events had rendered Prague obsolete. Russia’s first invasion of Ukraine in 2014 and its growing reliance on nuclear coercion shattered any hope that nuclear weapons could be rung out of European security. It is telling that Obama did not even mention the Prague speech in his memoirs.

The lesson was clear: nuclear policy cannot be separated from the broader strategic environment.

The advocates of the Nuclear Ban Treaty attempted to do just that—and produced a treaty largely ignored by the states whose arsenals matter most.

Russia and China Never Shared the Vision

Western idealism also rested on a faulty premise: that other great powers shared America’s disarmament aspirations. They did not.

Russia signed multiple arms control agreements between 1991 and 2011—but not because it believed in nuclear abolition. Moscow sought to maintain strategic parity with Washington while modernizing its vast tactical nuclear arsenal, which remained outside treaty constraints.

China’s trajectory is even more striking. When I testified before Congress on the subject in 2018, China possessed roughly 200 nuclear weapons. Today it has around 600. U.S. intelligence estimates project 1,000 warheads by 2030 and 1,500 by 2035.

As the Office of the Director of National Intelligence has noted, “China remains intent on modernizing, diversifying, and expanding its nuclear posture.” Beijing never intended to cap its arsenal—much less reduce it.

The Waning of American Security Guarantees

For seven decades, the most effective nonproliferation instrument has not been a treaty but the U.S. extended deterrent. Japan, South Korea, Germany, and other technologically advanced states refrained from pursuing nuclear weapons because they believed Washington would defend them in a crisis.

But this confidence has begun to erode.

Under President Donald Trump, allies have questioned whether U.S. commitments remain reliable. Regardless of whether such doubts are fair, the perception matters. In South Korea, support for indigenous nuclear weapons programs now routinely exceeds 60 percent.

Japanese leaders speak more openly about security options that were once taboo. Eastern European states debate expanding NATO’s nuclear-sharing arrangements.

If U.S. guarantees weaken further, the global nonproliferation regime could begin to unravel—not because treaties fail, but because allies no longer trust the assurances that made those treaties possible in the first place.

Extended deterrence remains the centerpiece of global nonproliferation. If it frays, proliferation will likely follow.

Ukraine and the Hard Lessons of War

The war in Ukraine has delivered the clearest indictment of post–Cold War disarmament thinking.

First, the Budapest Memorandum—under which Ukraine gave up the nuclear weapons left on its territory in exchange for assurances of sovereignty—proved hollow. Russia violated it in 2014 and again in 2022.

For many states, the lesson is stark: a nuclear weapon is a more reliable guarantor of sovereignty than a political assurance.

Second, Russia’s nuclear arsenal has constrained U.S. and NATO intervention. Washington has calibrated military assistance to avoid triggering Russian nuclear escalation. Meanwhile, NATO’s nuclear capabilities likely deterred Moscow from attacking bases inside Poland that support Ukrainian forces.

Nuclear deterrence is shaping the conduct of the war on both sides.

The broader lesson is unambiguous: nuclear weapons remain central to modern conflict dynamics. States that possess them can deter foreign intervention; states without them are vulnerable. For countries living near revisionist powers, the gap between a security assurance and a nuclear guarantee has never been clearer.

A New Nuclear Era

The optimism of the early 1990s has given way to a far more sobering reality: a world defined by major-power competition, nuclear modernization, eroding security guarantees, and active conflict on NATO’s borders. It is a world in which nuclear weapons are gaining—not losing—strategic value.

The disarmament agenda did not collapse because of insufficient moral resolve. It collapsed because the world changed. Russia, China, and North Korea, never embraced abolition. And U.S. allies, once comfortable relying on American protection, are now reconsidering their options.

In this environment, pursuing sweeping disarmament initiatives like the Nuclear Ban Treaty is not only unrealistic—it is strategically dangerous.

The priority must instead be maintaining credible deterrence, strengthening extended nuclear guarantees, and investing in practical risk-reduction measures that lower the chances of miscalculation or unintended escalation.

We are entering a new nuclear era—one less stable, less predictable, and less forgiving than the world many hoped would emerge after the Cold War.

Our task is not to lament that lost moment, but to build a strategy suited to the world as it is. That means deterrence, stability, and realism—not wishful thinking.

is President of Chevalier Strategic Advisors, a strategic advisory firm focused on the intersection of geopolitics and defense technology.  He previously served as Principal Deputy Administrator of the National Nuclear Security Administration (2021-2024), U.S. Assistant Secretary of State for Arms Control (2014-2017), a Professional Staff Member on the House Armed Services Committee (2007-2009), and as a Policy Advisor at the U.S. Department of Defense (1999-2006).

This article was originally published by RealClearDefense and made available via RealClearWire.