There’s a broiling debate about nuclear weapons going on, one reminiscent of Cold War debates over the implications of possible modifications to the U.S. nuclear arsenal. Some government officials have expressed an interest in having scientists at the national labs examine the potential for modern, precision, low-yield nuclear weapons, the prospective goal being to strengthen the U.S. capability to deter attacks. If ever developed, such capabilities would stand in contrast to the generally high yields and moderate accuracies of the remaining Cold War nuclear arsenal that was deployed to deter the Soviet Union.
Opponents of examining the potential for precision, low-yield weapons argue that a president will be more likely to employ a low-yield and thus relatively less-destructive nuclear weapon–in other words, the nuclear threshold will be lowered. So, they say, the United States should not even explore the concept. But the assertion that moving toward modern, low-yield nuclear weapons will lower the nuclear threshold is based on the mistaken belief that technical factors such as yield and accuracy will determine whether a president employs a such a weapon. This is suspect for several reasons.
It has long been recognized in the United States that nuclear weapons are not simply larger versions of conventional weapons, whose use in response to an attack is determined largely by technical considerations. Rather, the U.S. would consider employing a nuclear weapon only in the most extreme of circumstances–for example, if urban areas in the United States or a closely allied country were attacked with nuclear weapons or other WMD. This is why only the president can authorize the use of U.S. nuclear force.
In particular, a decision to cross the nuclear threshold for the first time since World War II–regardless of a weapon’s yield or accuracy–would be an act with extraordinarily high political consequences, and would be considered as such. In short, because we see nuclear weapons as occupying a special category–and because consideration of nuclear employment is plausible only in the most extreme circumstances–those circumstances will dominate the consideration. To believe otherwise reveals a naïve technical determinism that simply does not reflect the obvious facts in the United States.
The history of the nuclear age validates this point about presidential decision-making and nuclear weapons. Since World War II, the gravest crises during which U.S. presidents considered the nuclear option occurred when the United States possessed numerous, low-yield nuclear weapons. Even in these crises, with large numbers of low-yield nuclear weapons readily available, no president considered the threat grave enough to warrant crossing the nuclear threshold. In fact, in every case there is ample evidence that the question of nuclear employment was deliberated with the gravity appropriate to such a momentous political decision. Indeed, on the only occasions when atomic weapons were employed, it is clear that President Truman’s decision to use them was driven not by the technical details of the available weapons but by the extreme political circumstances of the time.
Finally, the assertion that reducing a weapon’s yield lowers the nuclear threshold mistakenly equates how an opponent perceives the possibility of U.S. nuclear employment with how a president perceives it. While technical details will not determine a president’s decision-making for the reasons described above, they may affect how opponents perceive U.S. deterrent threats. Effective deterrent threats must be credible to the opponent. Unfortunately, leaders of terrorist states and tyrants who recognize the appropriate priority we place on avoiding civilian casualties may not believe U.S. deterrent threats that would produce the high yields and moderate accuracies of the remaining Cold War arsenal.
Aggressors typically search for any rationale to believe what they most want–that their aggression will not generate strong opposition or entail high costs to themselves. We don’t want the technical character of our forces to provide such leaders with a rationale for dismissing the credibility of our deterrents. Should future U.S. deterrent-threat options incorporate low yields and precision accuracies, they could help deter our opponents’ use of WMD by minimizing the prospect that they will doubt us.
In other words, precision, low-yield weapons could potentially strengthen our capability to deter nuclear and other WMD attacks without the risk of lowering the nuclear threshold in a president’s thinking. And, ultimately, if an enemy’s attack is so extreme that nuclear retaliation is warranted, shouldn’t the president have a response option that incorporates very low-yield and precision accuracy?
We should not, as some now argue, preclude the possibility of developing these capabilities and thus limit our future nuclear retaliatory options to those that could inflict maximum levels of unwanted and otherwise avoidable civilian casualties.
–Keith Payne is president of the National Institute for Public Policy. He served as deputy assistant secretary of Defense for forces policy from 2002-2003.