On April 15, 2021, Senator Elizabeth Warren and Representative Adam Smith introduced legislation that declared, “It is the policy of the United States to not use nuclear weapons first.” Other Members of Congress are divided on this issue. Senator Dianne Feinstein has argued that the only moral use for U.S. nuclear weapons is as a deterrent to their use. Senator Deb Fischer, on the other hand, has said that the proposal “betrays a naïve and disturbed world view.” President Biden has spoken, in the past, about his support for a “sole purpose” policy for nuclear weapons, which some see as similar to “no first use,” but the President has not yet taken steps to review or alter U.S. nuclear policy.

A “no first use” policy would represent a change from current policy, where the United States has pledged to refrain from using nuclear weapons against most non-nuclear weapon states, but has neither ruled out their first use in all cases nor specified the circumstances under which it would use them. This policy of “calculated ambiguity” addressed U.S. concerns during the Cold War, when the United States and NATO faced numerically superior Soviet and Warsaw Pact conventional forces in Europe. At the time, the United States not only developed plans to use nuclear weapons on the battlefield to disrupt or defeat attacking tanks and troops, but it also hoped that the risk of a nuclear response would deter the Soviet Union from initiating a conventional attack. This is not because the United States believed it could defeat the Soviet Union in a nuclear war, but because it hoped the Soviet Union would know that the use of these weapons would likely escalate to all-out nuclear war, with both sides suffering massive destruction.

Since the end of the Cold War, the United States has modified its declaratory policy to reduce the apparent role of nuclear weapons in U.S. national security, but it still has not declared that it would not use them first. In the 2010 Nuclear Posture Review Report, the Obama Administration stated that the United States “would only consider the use of nuclear weapons in extreme circumstances” and would not threaten or use nuclear weapons, under any circumstances, “against non-nuclear weapons states that are party to the Nuclear Nonproliferation Treaty and in compliance with their nuclear non-proliferation obligations.” But the Administration was not prepared to state that the “sole purpose” of U.S. nuclear weapons was to deter nuclear attack because it could envision “a narrow range of contingencies” where nuclear weapons might play a role in deterring conventional, chemical, or biological attacks.

The Trump Administration, in the 2018 Nuclear Posture Review (NPR) Report, also rejected the idea that the sole purpose of nuclear weapons is to deter nuclear attack, and, therefore, also did not adopt a “no first use” policy. It noted that “the United States would only consider the employment of nuclear weapons in extreme circumstances to defend the vital interests of the United States, its allies, and partners” but stated that nuclear weapons contribute to “deterrence of nuclear and non-nuclear attack; assurance of allies and partners; achievement of U.S. objectives if deterrence fails; and the capacity to hedge against an uncertain future.”