The US nuclear policy introduced by President Dwight D. Eisenhower was called the New Look. Announced in the mid-1950s, it sought to contain the Soviet Union while reducing the cost of maintaining large conventional forces.
The strategy placed greater reliance on nuclear weapons, strategic air power, and the threat of massive retaliation. Eisenhower’s administration believed that the United States could deter aggression with its nuclear arsenal instead of matching the Soviet Union soldier for soldier across the globe.
The New Look influenced defense planning, alliance strategy, and budget priorities during the early Cold War. It also helped establish the idea that nuclear deterrence was central to US security policy, although the approach carried the dangerous risk that a local conflict could escalate into a general nuclear war.
Massive Retaliation is the common answer to a related question, but it describes a major doctrine associated with the New Look rather than the broader policy’s name. Flexible Response came later, becoming especially associated with the Kennedy administration’s effort to provide more options between inaction and all-out nuclear war.