The logic of nuclear deterrence.

Deterrence means that if two countries both have nuclear weapons, neither side is likely to start a war because the consequences would be catastrophic.

This is sometimes called Mutually Assured Destruction.

During the Cold War, both the United States and the Soviet Union built enormous nuclear arsenals.

Yet despite intense rivalry and proxy wars, they never fought a direct war.

The reason: both knew that nuclear retaliation would destroy both countries.

So in that sense, nuclear weapons can actually prevent large-scale wars between nuclear states.

Not every nuclear-armed country is treated as equally threatening.

Today the recognized nuclear powers include:

United States

Russia

China

United Kingdom

France

India

Pakistan

North Korea

Israel (widely believed to have them, though not officially declared)

Most of these countries are not expected to launch nuclear attacks because their doctrines focus on deterrence or retaliation.

North Korea illustrates the deterrence argument well.

North Korea is economically weak and diplomatically isolated, yet it developed nuclear weapons, tested ballistic missiles and publicly declared a nuclear doctrine.

Because of that capability, many analysts believe outside powers are very cautious about military intervention there.

In other words, nuclear weapons give a state a powerful survival guarantee.

The concern around Iran isn’t simply that it might obtain nuclear weapons.

The concern comes from several factors:

1. Israel’s security fears

Israel is geographically small and views any hostile nuclear power in the region as an existential risk.

2. Regional instability

Iran is involved in multiple regional conflicts and supports armed groups in neighboring countries.

3. Nuclear proliferation risk

If Iran becomes a nuclear state, countries like Saudi Arabia, Turkey, or Egypt might pursue nuclear weapons too.

That could create a multi-state nuclear arms race in the Middle East, which many analysts see as highly unstable.

This leads to a paradox sometimes called the “stability–instability paradox.”

The idea is:

Nuclear weapons make large wars less likely but they may make smaller conflicts more likely, because countries feel protected from full-scale retaliation.

For example, nuclear-armed states may feel freer to engage in proxy wars, cyber attacks and regional military operations.

So the real debate isn’t just whether Iran would use nuclear weapons.

It’s about how nuclear weapons change the strategic balance of an entire region.

Some experts argue a nuclear Iran would behave like other nuclear states and become more cautious.

Others argue it would trigger regional proliferation and instability.

Both perspectives exist among scholars and policymakers.

Nuclear weapons often function less as offensive weapons and more as political insurance policies for regimes.