Yesterday the Center for Strategic and Budgetary Assessments unveiled a new study by Todd Harrison and Evan Montgomery on the cost of U.S. nuclear forces. The study contains a wealth of data on the cost of the nuclear arsenal and the impending modernization of its delivery systems. However, a few thoughts following Harrison and Montgomery’s presentation are in order.

During his portion of the presentation, Harrison spent a great deal of time discussing the method used to determine the cost of a variety of nuclear systems. This sort of effort is always tricky; considering that many nuclear systems also have conventional uses, the nuclear-specific personnel and operating costs need to be extracted. Other studies, such as a 2012 Stimson Center report, have attempted to do this. As Harrison notes in differentiating their method from that of the Stimson report, systems that would still exist even if the nuclear arsenal were eliminated must be excluded from the nuclear-force cost estimate. Then reasonable assumptions need to be made about the portions of the remaining dual-use systems dedicated to the nuclear mission. The study also factors in inevitable cost overruns in modernization programs, using historical overrun averages in similar programs.

Based on Harrison’s description, the report likely presents as accurate a picture as possible of the cost of U.S. nuclear forces. But while the method is sound, there is an issue with how Harrison and Montgomery framed their presentation. The authors argue that searching for savings in the nuclear arsenal is largely quixotic. Borrowing from another author, they refer to it as a “hunt for small potatoes.”

And they are correct that the savings available from cuts in U.S. nuclear forces are small relative to the rest of the defense budget. As Harrison noted, the nuclear arsenal today is affordable at only around 3 percent of national defense spending, and will only reach 5 percent at the high point of an impending effort to modernize the nation’s nuclear-delivery systems. But as veteran defense reporter Bill Sweetman noted in the question-and-answer portion of the event, when you add up a lot of “5 percents” you generate greater savings. The nearly $20 billion in savings that Harrison and Montgomery say might be possible between now and the end of the decade from cuts in the nuclear force will not by themselves make up the difference between the Budget Control Act spending caps and Pentagon plans over the same period. But no one should expect them to. It is unlikely that cutting any one program—or set of related programs—could make up that $140 billion gap over the next half decade. Smaller cuts to a number of programs, including but not limited to nuclear forces, are necessary to bridge that gap.

Where to find that number of smaller cuts is a matter of prioritizing. Harrison and Montgomery rightly note that setting priorities is particularly important since a “bow wave”—when spending will peak—is projected for both nuclear and conventional modernization programs starting in the mid-2020s. At that point, nuclear modernization will include procurement of the Navy’s Ohio-class ballistic-missile submarine replacement and the Air Force’s Long-Range Strike bomber, and plans will likely be finalized for a new intercontinental ballistic-missile program beginning early in the 2030s. At the same time, the bulk of F-35 Joint Strike Fighter buys will take place; the Navy will be upgrading a number of shipbuilding programs; and the ground forces will need to upgrade a number of combat and transport vehicles.

The authors acknowledge that choices will have to be made among these competing priorities. They note that military leaders have declared that the nuclear arsenal and the planned modernization programs are vital to the country’s national security. But how often do military leaders and defense officials argue against the vitality of their own programs? Moreover, it is unlikely that any individual military service will break ranks with its brethren to argue that another’s program should receive the axe to preserve its own. These tendencies suggest prioritizing will be difficult.

Finally, even if the nuclear forces should be given priority, the current force structure could be changed to generate more savings. Harrison and Montgomery argue that this would require a change in America’s overall national security strategy. But it is unclear why that would the case. The nuclear force is currently an underfunded first-strike arsenal and an overfunded second-strike arsenal. Counterforce is a nuclear strategy that requires a first-strike to attack an adversary’s nuclear arsenal before it is launched in order to limit the potential damage it could inflict in retaliation or to provide the attacker with bargaining leverage. A first strike against Russia’s or China’s nuclear arsenals would require the United States to greatly expand its nuclear arsenal, possibly spurring those adversaries to expand their arsenals in response. Even if neither Moscow or Beijing responded in such a manner, a counterforce strike of the magnitude necessary to destroy their nuclear forces would be so destructive that threatening it might not be credible. The necessary expansion of U.S. nuclear forces would therefore be needlessly costly. A smaller force with a different force structure could generate savings and still provide the capability to promise retaliation against a Russian or Chinese first strike, as well as a counterforce capability against smaller nuclear powers such as North Korea.

These criticisms aside, Harrison and Montgomery have provided an invaluable resource for anyone seeking a better understanding of the cost of America’s nuclear arsenal. The method and cost projections will be useful for researchers trying to determine the extent of possible savings across a variety of force structures. Even if the authors consider those savings “small potatoes,” their study can provide the basis for a robust debate over where and how to prioritize the Pentagon’s competing modernization efforts.

Video of yesterday’s presentation is available here. Read their entire study here.