Applying physics to national security on Capitol Hill

Few members of Congress have technical backgrounds — a challenge when they're wrestling with issues like artificial intelligence or nuclear weapons systems. Ryan Nesselrodt spent a year trying to close that gap as an APS Congressional Science Fellow, translating scientific expertise into policy guidance for U.S. Rep. John Garamendi (D-CA).

“I used a technical approach to thinking things through, including laying out assumptions and seeing if those assumptions are correct, and breaking down problems into smaller parts,” recalls Nesselrodt, who drew on his physics background to advance policy in defense, energy, nuclear weapons, and infrastructure.

APS sponsors the fellowship under the umbrella of the American Association for the Advancement of Science’s Science and Technology fellowships. The fellowship makes individuals with scientific knowledge and skills available to members of Congress, and enables scientists to broaden their experience through direct involvement with policymaking.

Nesselrodt helped craft amendments for the National Defense Authorization Act, a federal law that outlines the Department of Defense’s budget, as well as amendments related to national security. One examined the risks of AI integration with nuclear weapons systems, prompting a Department of Defense report to Congress. Another called for a study on the reuse of plutonium pits, the core of nuclear weapons.

“Using my technical knowledge to help shape such an important piece of legislation was incredibly meaningful,” he says.

His work also connected him to the Congressional Nuclear Weapons and Arms Control Working Group, which Garamendi co-chairs. Nesselrodt helped organize briefings for the group that drew on the expertise of scientists “to help educate congressional staff about the technical challenges and costs behind missile defense,” Nesselrodt says.

A typical day during Nesselrodt’s fellowship: Read the morning headlines, then head into meetings. “On a light day, you might have one or two meetings,” he says. “On a busy day, I’d have 10 or 11. One time we met with every water agency in California in a single day.”

Between meetings, Nesselrodt coordinated with other offices and distilled lengthy reports into summaries for Garamendi. “Members of Congress have very limited time,” says Nesselrodt. “You have to understand what matters to your congressional member and communicate the bottom line quickly.”

That environment also demands an ability to pivot on short notice. “I like to call it ‘chaos management,’” he says. “You’re constantly moving from one issue to another and must maintain accuracy and attention to detail.”

Rob Hurd, legislative director for Garamendi, praised Nesselrodt. “Our office tackles a wide range of complex issues, including energy, defense, nuclear non-proliferation, and water management, and Ryan made a meaningful impact in each of those areas,” he says.

Hurd also highlighted Nesselrodt’s role in advancing the Ships for America Act, introduced by Garamendi to revitalize the U.S. shipbuilding industry. “Ryan helped build support for the bill, organized briefings, and informed negotiations,” Hurd says. “He significantly enhanced our understanding of key issues.”

Today, Nesselrodt is working in Garamendi’s office on a short-term extension. In the future, he hopes to remain in policy, either as a congressional staffer or in a D.C.-based think tank, focusing on technology, energy, and nuclear oversight.

Nesselrodt describes the fellowship as “life-changing.”

“It was an eye-opening experience to see how science can inform public policy,” he says. “I’m deeply grateful to APS, to AAAS, and to Rep. Garamendi’s congressional office for giving me this opportunity.”