Washington: The demise of the New START treaty that limits US and Russian nuclear forces could wind up costing the United States as much as $439 billion in modernization costs, plus another $28 billion annually for maintenance of a souped-up nuclear arsenal, says a new study by the Congressional Budget Office (CBO).

Or it could cost almost nothing at all, says the CBO report, mandated by Democrats on the Senate and House Armed Services Committees.

“DoD’s one-time costs could range widely, from zero if the United States chooses not to make any changes to its current plans, to about $100 million to $172 billion if it expanded its (nuclear) forces to START II levels, to $88 billion to $439 billion if it expanded to START I levels,” CBO’s press release about the study, “The Potential Costs of Expanding US Strategic Nuclear Forces If the New START Treaty Expires,” says.

The estimates only cover costs to DoD for weapons platforms that deliver nukes (called Strategic Delivery Vehicles or SDVs), however. they don’t include development and manufacture costs of any new nuclear warheads, which are built and maintained by the Energy Department. But the study’s cost estimates for each scenario involving a build-up of the arsenal represent new costs — I.e. extra costs beyond currently planned spending for DoD on its on-going nuclear modernization effort. (CBO in January estimated the modernization effort will cost a total of $234 billion over the next 30 years.)

“The report shows that the already excessive and unsustainable financial costs to maintain and modernize the US nuclear arsenal could soar even higher if the treaty expires in five months with nothing to replace it and the United States choses to increase the size of the arsenal,” Kingston Reif, director of disarmament and threat reduction policy at the Arms Control Association, said.

The problem with calculating funding requirements is simply that there is no way to judge what a future president might decide about how many and what types of nuclear weapons platforms are needed because we won’t know as much about the size of the Russian arsenal once New START expires, a CBO official said.

That said, experts say that eventually the momentum toward a US nuclear build-up would become almost unstoppable. Indeed, the need for transparency into each other’s nuclear force structure to serve as a brake on a run-away arms race was the entire reason behind the US-Soviet arms control treaties in the first place.

“If the Russians start building up, our history suggests that our reaction will be to do the same. And in fact, if we thought the Russians were starting to build up — because of course we won’t know anymore because we can’t verify — then history would suggest that we would also build up. So I think there will be some real pressures to build up,” said one long-time arms control analyst.

“Ever-increasing spending on nuclear weapons without an arms control framework that bounds US and Russian nuclear forces is a recipe for budget chaos, undermining strategic stability, and damaging the health of the global non-proliferation regime,” Reif said.

Because there is no way to predict the size of a future US nuclear arsenal — and just as importantly the mix of ICMBs, bomber and nuclear submarines making it up — CBO chose to price out cost ranges for arsenal sizes based on weapons caps included in three former US-Russian treaties: the 1991 Strategic Arms Reduction Treaty (START) I; the 1993 START II; and the 2002 Strategic Offensive Reductions Treaty (SORT), but more commonly called the Moscow Treaty).

“The lower end of each of those ranges reflects a lower-cost, less-flexible approach that emphasizes loading more warheads on each missile and buying fewer new systems; the upper end reflects a more-flexible, higher cost approach that emphasizes keeping warhead loadings on missiles similar to what the United States deploys today,” CBO’s release explains.

The study does note that expanding the nuclear arsenal could take many years. “Available warheads could be uploaded relatively quickly, but additional delivery systems and warheads would probably not be available before the late 2030s or early 2040s. Most of the additional costs of expanding forces would thus occur a few decades from now.”

In addition, to aid future analysts as decisions are made about purchasing new platforms, CBO provided estimates for buying additional delivery platforms equipped for carrying their maximum number of warheads (i.e., one additional SSBN ballistic missile submarine, one B-21 bomber, and 10 new Ground-Based Strategic Deterrent (GBSD) silos. For example, the study finds that 1 B-21 with 10 Long-Range Stand-Off (LRSO) cruise missiles and capable of launching eight nuclear warheads would cost $500 million, and $40 million a year (in 2020 dollars) to maintain.

New START, currently the only remaining US-Russia treaty capping nuclear weapons arsenals, will expire in 2021. The treaty limits Russia and the US each to no more than 1,550 deployed strategic warheads and 700 deployed strategic delivery vehicles (meaning ICBMs, submarines and bombers).