President Donald Trump’s nominee to be an assistant secretary for the Defense Department’s nuclear, chemical, and biological defense programs believes that the U.S. has the right to preemptively unleash nuclear weapons on other countries.

The New Republic‘s Emily Atkin wrote on Friday that Trump has nominated Guy B. Roberts to — according to the job description posted on the DoD website — “prevent, protect against, and respond to weapons of mass destruction threats” and advise Defense Sec. James Mattis on “matters concerning nuclear, chemical, and biological defense programs.”

Roberts, Atkin said, has a strong resume. He is a 25-year veteran of the Marine Corps and has worked in nuclear weapons policy for NATO.

However, he is a strong proponent of the controversial doctrine of “first-use nuclear policy,” the belief that the U.S. reserves the right to strike other countries with nuclear weapons at will.

Pres. Barack Obama considered joining a “no first-use” pact, which Roberts responded to in 2016 with an essay for The National Interest titled “America Must Be Ready to Nuke First.”

In the essay, Roberts argued that the U.S. must function as a bulwark against Russian military aggression.

“While the Obama administration contemplates a no-first-use policy, the Russians threaten the opposite: first, to intimidate and coerce U.S. allies and partners; and second, as part of a strategy of escalation, to de-escalate (that is, less apt to provoke a nuclear response and more conducive to war termination than second use),” Roberts wrote. “Russian military doctrine explicitly states that Russia would consider using nuclear weapons in response to ‘conventional aggression’ if it endangers the existence of the state, and recent Russian exercises demonstrate Russia’s intent to use nuclear weapons first in a conventional conflict.”

International leaders are increasingly nervous and wary about Trump’s unpredictability and his ready access to nuclear weapons.

Department of Defense officials are concerned that the U.S. is losing its position of military supremacy in the world and have advocated a policy of increasing “military dominance.”