In Conversation - Prof Pelopidas, Sciences Po

Nuclear Deterrence Theory

In a recent discussion with Benoît Pelopidas, a leading scholar of nuclear policy at Sciences Po, I explored his provocative critique of nuclear deterrence theory. His research challenges the foundational assumptions that have justified nuclear arsenals for over seven decades.

Pelopidas argued that deterrence theory rests on unverifiable claims. We cannot prove that nuclear weapons prevented World War III because we cannot observe the counterfactual. The Cold War's peaceful conclusion might have resulted from factors entirely unrelated to nuclear arsenals, yet policymakers and strategists attribute stability to deterrence almost reflexively. This creates a dangerous feedback loop where nuclear weapons are credited for peace they may not have secured.

The psychological dimension is critical. Pelopidas emphasized that deterrence assumes rational actors who calculate costs and benefits accurately under extreme pressure. Yet historical evidence reveals numerous close calls where accidents, misperceptions, and bureaucratic failures nearly triggered nuclear war. The Cuban Missile Crisis, often cited as proof of deterrence working, actually demonstrates how close we came to catastrophe despite rational leaders.

His work also examines how nuclear weapons shape strategic thinking. Once states acquire nuclear capabilities, they develop doctrines and institutions that entrench these weapons into national security planning. This path dependence makes disarmament politically difficult even when strategic conditions change. Nuclear weapons become symbols of prestige and sovereignty rather than purely military tools.

What makes Pelopidas's research compelling is its focus on existential risk. Even a small probability of nuclear use, multiplied across decades, creates substantial accumulated danger. He suggested that our survival so far may owe more to luck than to deterrence strategy.

This conversation forced me to confront uncomfortable questions about security policy. If deterrence theory lacks empirical foundation, what alternatives exist? How do we navigate a world where nuclear weapons exist regardless of their strategic logic?