By John Erath
The rapid collapse of the Afghan government and takeover by the Taliban have led to a great deal of wondering what went wrong and what lessons may be learned. The chain of events, successes, and many missteps will naturally be studied by scholars and experts in international security and will hopefully inform policy making in ways that will avoid some of the worst mistakes and lead to better decision making. One aspect of the events of recent weeks that bears further study is the way we think about deterrence.
The United States has been drawing down its forces from Afghanistan for years, beginning with the Obama administration, continuing with President Donald Trump’s efforts to end the mission, and concluding under the Biden administration. Whereas at the height of the Obama “surge” there were around 100,000 troops deployed, by the end of the Trump administration, only about 2,500 remained.
There were many complicating factors, including the presence of al Qaida, numbers of allied forces, and changes in local politics, but the point is that the Pentagon was able to limit the opposition to insurgency tactics and harassment operations with only a small number of troops, many fewer than what the Taliban could field. The insurgent leadership was convinced that efforts to capture major population or economic centers would provoke a strong military response, so they waited for the final troops to be withdrawn. This is deterrence.
In the context of nuclear weapons, deterrence works differently. The stakes are far higher and the consequences of a misstep would be far more extreme.
There is, however, a lesson to be learned from the Afghan withdrawal that merits consideration. Deterrence is not necessarily a question of math. In order for it to function, there need not be absolute parity in nuclear weapons, nor does the United States need superior numbers to deter potential aggressors effectively. Just as 2,500 well equipped troops were enough to keep many thousands more Taliban fighters from taking over, it is possible that a relatively small number of nuclear weapons will be able to deter even a nuclear armed adversary.
Deterrence, however, is not a science and the exact level of force needed will be difficult to ascertain, but it is clear that trying to match amounts with potential foes is not necessary, especially given U.S. qualitative superiority.
As the White House and Pentagon move forward with the Nuclear Posture Review, they should base decisions on future levels of nuclear forces on analysis of what is needed for actual deterrence, not estimates of someone else’s forces. Doing so would potentially save a great deal of taxpayers’ money without compromising national security.