Build Only One Type of Nuclear Weapon for Bombers

Long-range bombers are the most visible of the three components of the strategic nuclear triad, which also includes intercontinental ballistic missiles and submarine-launched ballistic missiles. Since 1945, the United States has used nuclear-capable bombers to deter adversaries and assure allies during crises by raising the pace of their operations or deploying the aircraft to areas of potential conflict. For bomber weapons to be effective, they must be able to penetrate air defenses to reach their targets. To ensure that they are able to do so, the Air Force relies on hard-to-detect platforms, including cruise missiles that can deliver a warhead when launched from a bomber operating safely away from air defenses and stealthy manned bombers that can fly into defended airspace and deliver short-range gravity bombs from directly above targets. Currently, the Air Force fields two types of long-range bombers that can carry nuclear weapons, both of which can also perform conventional missions: the B‑52H, which carries the Air-Launched Cruise Missile (ALCM), and the stealthy B‑2A, which carries several varieties of nuclear gravity bombs.

The major pieces of the nuclear bomber force are slated for modernization over the coming decades through the combined efforts of the Department of Defense (DoD) and the Department of Energy (DOE). The most expensive program related to that modernization effort is the development of a new stealthy bomber, the B-21. Two other programs focus on the development of new weapons for that bomber. In one, the B61-12 life extension program (LEP), DOE is working to refurbish and combine several varieties of the B61 bomb into a single hybrid design. In the other, DoD is developing the Long‑Range Standoff Weapon (LRSO), a new nuclear air-launched cruise missile that will carry a warhead that DOE will produce. Plans call for the B‑21 to be capable of carrying both the B61‑12 bomb and the LRSO.

This option would cancel one of the two new weapons and limit the United States’ nuclear arsenal to a single type of weapon that could be carried by bombers in the future. The option includes two alternatives. The first would cancel the LRSO but retain the B61‑12 LEP. After the nuclear cruise missiles that are currently in service reached the end of their operational lifetime, strategic bombers would no longer be equipped with such missiles. The second alternative would do the opposite—cancel the B61‑12 LEP and retain the LRSO. Under that alternative, after the nuclear bombs that are currently in service reached the end of their operational lifetime, strategic bombers would cease to carry such bombs. Canceling the B61‑12 program would also eliminate the option to deploy that weapon on tactical fighter aircraft based in Europe. Neither variant of this option would change the planned size of the strategic bomber fleet. Only one version of the option or the other could be implemented without eliminating the nuclear capability of the bomber component of the nuclear triad.

One argument in favor of this option is that by equipping bombers with a single type of nuclear weapon, the United States could reduce costs while still retaining the ability to deploy nuclear bombers. In addition, the timing of the option makes the savings particularly beneficial: The savings would occur when nearly all other components of the United States’ nuclear forces are currently scheduled to be modernized. Over the next 20 years, the modernization efforts are expected to roughly double the total amount that the United States spends annually on nuclear forces (currently about $20 billion).

An argument against canceling the development of one type of bomber weapon is that doing so would reduce nuclear capabilities at a time when international tensions, particularly with Russia and China, might make reductions risky. The impact of the option on the United States’ nuclear capabilities would depend on which alternative was pursued.

Cancel the Long-Range Standoff Weapon

Under the first alternative, the Air Force would stop equipping bombers with cruise missiles armed with nuclear warheads after the current ALCMs reached the end of their service life around 2030. Specifically, DoD would cancel development and production of the LRSO, and DOE would cancel the development and production of the associated warhead. That approach would reduce the need for discretionary budget authority by $9 billion over the next decade, the Congressional Budget Office estimates. Outlays would decrease by $8 billion. Additional savings would accrue after the 10-year projection period by eliminating both the cost of the additional LRSO missiles and warheads that are currently slated for purchase after 2026 and the expense of operating the new systems.

One argument for canceling the LRSO program is that the need for nuclear cruise missiles has been significantly reduced by the development of modern conventional cruise missiles, which can perform most of the same missions. In addition, to maintain the ability to conduct missions requiring nuclear weapons, some analysts argue, the LRSO program could be postponed until adversaries’ air defenses advanced to the point that the B-21 could no longer penetrate them.

An argument against canceling the development of new air-launched cruise missiles is that doing so would somewhat diminish the capabilities of U.S. nuclear forces, particularly the forces’ capacity to carry out limited nuclear strikes. Cruise missiles offer operational planners flexibility because they can travel for extended distances (the unclassified range for the current ALCM is more than 1,500 miles) along complicated flight paths, potentially allowing bombers to avoid dangerous or sensitive areas. Thus, removing air-launched cruise missiles would be more detrimental to the Air Force’s strategic nuclear capabilities than eliminating nuclear bombs, which must be dropped in close proximity to a target.

Cancel the B61-12 Life Extension Program

Under the second alternative, the United States would cancel the B61-12 program and the associated program that is developing improved guidance kits for the bombs. Strategic bombers (and tactical fighters) would no longer be equipped with nuclear gravity bombs after current models reach the end of their service life. This version of the option would reduce the need for discretionary budget authority by about $6 billion over the next decade. The decrease in outlays would be slightly smaller.

One argument for canceling the B61-12 LEP is the potential that the costs of the program will grow: Early cost estimates varied widely, and the DOE’s current estimates are substantially lower than an independent estimate from DoD, so the actual costs may exceed them. Furthermore, the planned guidance systems are considered by some analysts to be a significant improvement in performance and thus contradict the United States’ publicly declared policy of not developing new nuclear military capabilities. Moreover, like those of the bombs that it will replace, the nuclear yield of the B61-12—that is, the amount of nuclear energy that it releases upon detonation—will be variable. Many analysts argue that the improvements in accuracy on the B61-12 would allow it to destroy a larger set of targets at a low-yield setting than current bombs can and that the availability of such advanced low-yield weapons might increase the likelihood that nuclear weapons would be used.

An argument against the second alternative is that, in addition to strategic nuclear bomber capability, it would also affect the United States’ short-range nuclear capabilities. The B61-12 is slated to be carried not only by the long-range B-21 but also by shorter-range tactical aircraft; those shorter-range aircraft do not carry nuclear cruise missiles. The United States fields such nuclear-equipped tactical aircraft at bases in Europe, where it also has nuclear bombs that could be carried by those aircraft or by the tactical aircraft of its allies in the North Atlantic Treaty Organization (NATO). If the B61-12 LEP was canceled, U.S. policymakers might choose to eliminate that tactical nuclear mission. Such a choice, however, would probably be opposed by other NATO member nations given current tensions between NATO allies and Russia. If the United States chose to continue the tactical nuclear mission, it would need to overhaul the tactical varieties of the B61 when they reached the end of their lifetime or seek some other solution, such as adapting the LRSO for tactical missions. Any of those approaches to preserve the tactical nuclear mission would reduce—and, in some cases, perhaps even negate—savings from this alternative, but those effects may occur beyond CBO’s 10-year projection period.