The world is entering a decisive period for nuclear security, former Under Secretary of Energy for Nuclear Security Jill Hruby said during the 2025 Drell Lecture at the Center for International Security and Cooperation (CISAC) at Stanford University.

Speaking at the Bechtel Conference Center on Wednesday, October 29, Hruby described the next five to ten years as a “nuclear tipping point” that will determine whether arms racing and proliferation are constrained or accelerate into a more dangerous era driven by competition and emerging technologies.

The Drell Lecture is an annual public event sponsored by CISAC. By tradition, the Drell lecturer addresses a current and critical national or international security issue that has important scientific or technical dimensions. The Drell Lecture is named for Sidney Drell, CISAC's founding science co-director. Albert and Cicely Wheelon generously endowed the lectureship.

Jill Hruby served as the Under Secretary for Nuclear Security at the Department of Energy and Administrator of the National Nuclear Security Administration from July 2021 to January 2025.  Since early 2025, She has joined the Lawrence Livermore Board, the Anthropic National Security and Public Sector Advisory Committee, the Science and Security Advisory Board for the Bulletin of Atomic Scientists, and the Atomic Weapons Establishment Board. Hruby is currently the Payne Distinguished Lecturer at CISAC.

A worsening nuclear landscape

Hruby warned that no nuclear-armed state is currently reducing the size or capability of its arsenal. Instead, most are modernizing or expanding.

Russia’s war in Ukraine, she said, has heightened nuclear risks through explicit threats, actions around nuclear facilities, and continued investment in advanced delivery systems. China, meanwhile, is expected to reach nuclear peer status within the next decade, with rapid arsenal growth and new missile infrastructure, posing a deterrence challenge unlike the Cold War due to deep U.S.- China economic interdependence.

She also highlighted ongoing risks beyond the great powers, including North Korea’s expanding arsenal, evolving deterrence dynamics between India and Pakistan, and Iran’s shortened timelines for producing weapons-usable material.

Despite these trends, Hruby cautioned against alarmism, noting that nuclear testing remains dormant and major powers have largely observed strategic limits. This fragile balance, she said, is precisely what makes the current moment so consequential.

“That's the reason the words Nuclear Tipping Point seem appropriate with harmful decisions and actions, the dangers associated with nuclear weapons could remain understood and respected,” said Hruby. “The nuclear taboo could hold and nuclear proliferation could remain unchecked.”

How deterrence works and what it costs

A central theme of Hruby’s remarks was the need to raise America’s “nuclear IQ,” particularly among senior leaders. She outlined how nuclear responsibilities are divided between the Department of Defense and the Department of Energy and described the Nuclear Weapons Council as the key mechanism coordinating modernization, safety, and long-term planning.

Hruby also addressed the scale and cost of U.S. nuclear modernization, warning that the nuclear security enterprise is operating beyond post-Cold War assumptions. Deterrence, she argued, requires sustained investment over decades, not year-to-year budgeting, and greater honesty about the full lifecycle costs of nuclear weapons.

“The reality is that a safe, secure and effective nuclear stockpile is expensive. The costs don't go away once you have weapons. Investments are required over time, and systems don't last forever,” said Hruby

Science, credibility, and restraint

In discussion, Hruby emphasized the importance of science-based stockpile stewardship, arguing that the United States may understand nuclear weapon behavior better today than during the era of explosive testing. At the same time, she warned against complacency and stressed the need for continuous scientific vigilance.

She also cautioned that ambitious missile defense concepts could increase instability by encouraging adversaries to expand or diversify their arsenals, underscoring the need to pair technical initiatives with diplomacy.

A call for engagement

Asked whether she felt optimistic, Hruby offered a nuanced answer: pessimistic in the near term due to worsening global behavior, but cautiously optimistic in the long run, as sustained escalation is ultimately irrational.

The lecture concluded with a call for broader engagement on nuclear issues. At a nuclear tipping point, Hruby argued, deterrence and responsible stewardship cannot remain the domain of a small expert community. They require wider understanding, informed debate, and sustained leadership.

“We got here together, and we need to work together to maintain effective nuclear deterrence, although it’s going to look different than it has in the past,” Hruby emphasized in closing. “There is never a good time to give up on balancing nuclear deterrence and responsible arms control.”