President Obama gave a speech this week at the Brandenburg Gate in Berlin calling for the United States and Russia to reduce the size of their deployed nuclear arsenals by one-third, to about 1,000 strategic warheads. The call for further cuts has been greeted with enthusiasm in many quarters, but these proposed nuclear reductions could be highly damaging to U.S. interests.
In his speech, the president argued that such cuts would be consistent with the goal of maintaining “a strong and credible strategic deterrent,” but this argument rests on a contested theory about how nuclear deterrence works. The Obama administration, and many scholars and experts, believe that a secure, second-strike capability is sufficient for deterrence and that anything more is “overkill.” Therefore, they believe that nuclear warheads in excess of a “minimum deterrent” threshold can be cut with very little loss to our national security.
However, there are those who argue that maintaining a nuclear advantage over one’s opponents enhances deterrence. As Paul Nitze argued during the Cold War, “the greater the margin (and the more clearly the communists understand that we have a margin), the less likely it is that nuclear war will ever occur.”
For decades, this debate was largely theoretical – neither camp marshaled systematic evidence in support of its views. But recently I methodically reviewed the relationship between the size of a country’s nuclear arsenal and its ability to achieve its national security objectives. I found strong evidence that when it comes to nuclear deterrence, more is better.
In an analysis of 52 countries that participated in nuclear crises from 1945 to 2001 (think the Cuban missile crisis), I found that the state with the greater number of warheads was more than 17 times more likely to achieve its goals. In addition, there is qualitative evidence from these crises that leaders in nuclear-armed states pay close attention to the nuclear balance of power, that they believe nuclear superiority enhances their position, and that a nuclear advantage often translates directly into a geopolitical advantage.
Even if Russia agrees to match the president’s proposed cuts, the nuclear reductions eat into our margin of superiority against other nuclear-armed states such as China, possibly increasing the likelihood that the United States will be challenged militarily and reducing the probability that we achieve our goals in future crises.
Supporters of further cuts argue that reducing the role of nuclear weapons in U.S. policy will help us stop the spread of nuclear weapons to other countries. They argue that our large nuclear arsenal makes it difficult (if not hypocritical) to tell, say, Iran that it cannot have nuclear weapons. Therefore, they argue, we can generate good will and strengthen our nonproliferation efforts by cutting our own nuclear arsenal.
This argument falls apart on closer inspection. As Iran’s leaders decide whether to push forward with, or put limits on, their nuclear program, they likely consider many things, but it is implausible that the precise size of the U.S. nuclear arsenal is among them.
The United States should refrain from making any additional nuclear reductions. It must not go below the 1,550 warheads agreed to in the New START Treaty (and it should take its sweet time getting down to that number). In addition, the United States should maintain the “hedge” of weapons it keeps in reserve at current levels. Finally, the Obama administration must follow through on its promise to fully invest in modernizing U.S. nuclear infrastructure so that it does not lose the capability to sustain a safe, secure and effective nuclear arsenal for decades to come.