Report Calls for Moving to U.S. Nuclear “Dyad,” Dropping Triad’s Bomber Leg

(Dec. 16) -A U.S. Air Force B-52 bomber departs from a British air base in 2003. An independent report calls for phasing out bomber aircraft from the U.S. nuclear deterrent (Julian Herbert/Getty Images).
(Dec. 16) -A U.S. Air Force B-52 bomber departs from a British air base in 2003. An independent report calls for phasing out bomber aircraft from the U.S. nuclear deterrent (Julian Herbert/Getty Images).

WASHINGTON -- A new, independent report recommends that the United States gradually phase out B-2 and B-52 bomber aircraft from its nuclear deterrent (see GSN, Oct. 1).

The move would be the ultimate result of arms control and weapons-acquisition trends that undercut the value of a nuclear role for these aircraft, according to a trio of aerospace experts writing for the Air Force Association's Mitchell Institute for Airpower Studies.

Under such an approach, the nation's nuclear triad would become a "dyad" comprising just submarine- and ground-launched ballistic missiles. The bombers would retain their conventional combat responsibilities, where their long range and large payloads continue to offer great military benefit, the analysts said.

The finding is immediately proving controversial, though, with Air Force officials insisting the bombers continue to play a unique and critical role in nuclear deterrence.

Anticipated reductions in the size of the U.S. nuclear stockpile prompted the new assessment. The United States and Russia are negotiating an arms control accord to replace the 1991 Strategic Arms Reduction Treaty, which expired Dec. 5. The pact is expected to cap deployed warheads as low as 1,500, down from the 2,200 warheads that the 2002 Moscow Treaty allows each side to field by the end of 2012.

Using the numbers projected for the so-called "New START" pact, the aerospace experts analyzed different force mix options. They concluded that the bomber leg of today's triad is declining in efficacy relative to ballistic missiles and could be safely eliminated.

"The United States should gradually shift to a dyad of submarine-launched ballistic missiles (SLBMs) and land-based intercontinental ballistic missiles (ICBMs) as it shapes its nuclear force posture for the future," said Dana Johnson, Christopher Bowie and Robert Haffa in the 32-page report, "Triad, Dyad or Monad? Shaping the U.S. Nuclear Force for the Future."

In fact, according to the analysis, the nation is already moving in this direction.

Although the Defense Department is funding the modernization of its ICBM and SLBM fleets and plans eventually to replace its nuclear-armed submarines, it is retiring Air-Launched Cruise Missiles carried by 94 vintage B-52 aircraft and has not funded a replacement.

"That's a clear indication that the Air Force doesn't want to put resources toward a new nuclear bomber," one retired service officer told Global Security Newswire this week.

The B-2 remains a modern bomber but there are only 20 of them, affording these aircraft only a "niche role," according to the authors. Plans for a Next-Generation Long-Range Strike system -- a future strategic bomber -- remain on hold pending additional work to clarify military requirements for the new aircraft.

"Unless this path is altered, the United States will soon field a de facto nuclear dyad," according to the study.

The authors -- all with the Northrop Grumman Analysis Center -- concluded that the current nuclear triad would be preferable to moving to a two-legged posture, but the elimination of atomic-armed bombers would not be a huge loss. Northrop Grumman, the corporate think tank's parent company, is nearing the end of a 15-year Air Force contract to help manage and modernize the nation's ICBMs, according to its Web site.

The group looked at a variety of options for nuclear monads and dyads, and found that an ICBM-SLBM combination compared most favorably to today's posture, on the basis of preserving nuclear deterrence and maintaining international stability during a crisis.

"The triad remains the most attractive overall strategic force structure option," the report states. However, if arms control and weapons-acquisition considerations push the nation in the direction of a dyad, the bomber leg would be the least necessary to maintain, the analysts said.

"We are not at all advocating that the bomber be removed from the triad, but the writing on the wall and the budgets that exist and the plans that are in the making suggest that the bomber leg will occupy a narrower and narrower contribution to strategic nuclear deterrence," Haffa said at a briefing sponsored by the AFA Mitchell Institute last Thursday. "So the term we coined was a 'de facto dyad.' We're nearly there today, and it looks from our judgment like we are headed in that direction."

Of the dyad options that the team examined, "the ICBM-SLBM combination offers the greatest similarity to the attributes of the current triad and appears to offer the most attractive alternative from a deterrence standpoint," the report reads. Alternative dyad options were bomber-ICBM and bomber-SLBM combinations.

The ICBM-SLBM dyad was capable of retaining 739 operationally deployed warheads on alert, "close to" the 829 warheads the analysts estimate are maintained on that launch-ready status today, the report states. The submarine-based fleet would continue to offer a highly survivable nuclear force, while the nation's 450 ICBMs represent a large number of warheads on alert, the authors said.

Though costs did not drive the analysis, a dyad approach would save significant dollars in the coming years compared to maintaining the triad, according to the report.

"The triad, the most attractive strategically, is also the most costly in both operating and investment costs," the analysts found, basing their data on fiscal 2010 dollars. They estimated that today's triad costs $5.4 billion to maintain and operate annually, and would require $240 billion between 2010 and 2050 to modernize.

By contrast, the ICBM-SLBM dyad option under a 1,500-warhead force would cost $3.7 billion to maintain and operate each year, and $151 billion to modernize by 2050.

"Because of the low cost of retaining the ICBMs, the most attractive dyad option (ICBMs and SLBMs) is roughly the same cost as the SLBM monad and would clearly be preferable," the analysts said.

The authors' five-point prescription for eventually phasing out the nuclear bomber role would be to:

-- "Maintain the 450 ICBM force in light of the declining bomber leg;

-- "Maintain the current ballistic missile submarine (designated SSBN) fleet and continue plans to develop the Ohio-class replacement" (see GSN, Nov. 7, 2008);

-- "Maintain and modernize the B-2 force to retain the capability to conduct discrete and selective nuclear strikes," for a limited amount of time until a dyad is realized;

-- "Phase out the B-52 from a nuclear role as ALCMs [Air-Launched Cruise Missiles] are retired from service [and];

-- "Divert any planned investments dedicated to maintaining the B-52 in a nuclear role -- including research and development of a new ALCM -- into a new conventional bomber, which could be manned or unmanned."

Neither cost nor force-structure arguments for eliminating a nuclear role for U.S. bombers are being publicly embraced by the Air Force, at least not immediately.

The report authors wrongly base their recommendations "on warfighting capability, missing the point that nukes are political and nukes are a deterrent," asserted Billy Mullins, Air Force associate assistant chief of staff for strategic deterrence and nuclear integration.

"Bombers have a very unique place in their being able to signal [intent]," he told GSN in an interview last week. "They're very visible when you generate them. ... Not as much when you flush subs, and definitely you can't tell anything is going on in the [ICBM] missile fields."

Haffa also praised some of the features that a nuclear bomber offers. It is perhaps the most flexible leg of today's triad, allowing commanders to deploy different mixes of bombs and missiles and, if necessary, summon them back to base if an attack is called off.

"The ability to alert it, the ability to move it, [and] the ability to send signals all are positive," Haffa said.

Several Air Force officials in the audience last week took issue with the authors' treatment of bombers, alleging that the team overemphasized the benefits of missiles and gave short shrift to the aircraft's most valued features. One said the team's cost estimates were skewed in a way that biased the conclusions against bombers.

"Some of the assumptions -- a lot of the numbers and math -- were off significantly enough to color your outcomes," said an Air Force colonel.

An analytical tool the group used in the report "doesn't tend to capture" the relative importance of the various attributes of the different legs of the nuclear triad, artificially weighing each attribute equally, another colonel complained.

Haffa noted that while the nuclear force remains important, Washington is grappling with rogue nations and violent extremists in the post-Cold War era. Under this altered security environment, it is increasingly desirable to use conventional forces to signal military intent and reassure allies of security guarantees, he said. Bombers carrying conventionally armed, precision-guided weapons pose a daunting threat to an adversary, and even a conventional bomber visibly put on alert could offer significant deterrence value, Haffa said.

"I would argue that the role of the strategic conventional bomber could be very strong in extending conventional deterrence that's capable, that's credible, that's reliable, that reassures our adversary [of intent] and perhaps has much more possibility in terms of use, as we've demonstrated, than a nuclear bomber might bring," Haffa said.

Without top-level support from Defense Secretary Robert Gates, though, it is unclear whether Air Force Secretary Michael Donley or Chief of Staff Gen. Norton Schwartz might be expected to embrace such an argument.

Gates last year fired Donley's and Schwartz's predecessors -- then-Secretary Michael Wynne and Chief of Staff Gen. Michael Moseley -- citing a "lack of effective Air Force leadership oversight" and commitment when it came to nuclear weapons. The highly public ousters followed revelations about major incidents in which the service had lost tight control over nuclear weapons and components (see GSN, June 6, 2008).

Since then, the Air Force has altered its bomber aircraft training to improve security and readiness, among other measures. However, some critics charge that the Defense Department has overreacted in ushering in these Air Force changes, sapping resources and focus away from crucial conventional combat missions (see GSN, April 27).

Behind the scenes at the Pentagon, there might be substantial support for gradually shedding the bomber's nuclear role, according to some sources.

"The Air Force and DOD have seriously considered going conventional-only [on the] bombers," said the retired service officer, speaking on condition of not being named in discussing a politically sensitive matter. "I don't know that the Air Force is particularly an advocate for the nuclear bomber today."

That said, "I don't believe that the current leadership of the Air Force is willing to expose themselves to not aggressively pursuing nuclear forces," according to this source. "But clearly I think they look at the nuclear mission as being marginal."

Haffa said there are practical considerations that might force the matter in the coming months, as New START details become known and major Pentagon studies on future nuclear and conventional forces -- the Nuclear Posture Review and Quadrennial Defense Review -- are delivered to Congress.

Dual-use bombers that have both conventional and nuclear roles could prevent Washington from fully populating its shrinking atomic arsenal under anticipated arms control treaty provisions, he explained.

If a next-generation bomber is built for both nuclear and conventional missions -- as B-2 and B-52 crews are trained to perform today -- the United States might be forced to count these aircraft under atomic warhead limits, even if they are not always armed with such weapons, Haffa said.

Under the just-expired START accord, the nation has had to count hundreds of "phantom" weapons against warhead limits, but lower caps would make such a practice even less desirable, analysts say.

Meanwhile, moving toward a conventional-only designation for bombers might well enhance the aircraft's utility, Haffa argued.

"What is the future of the bomber?" Haffa said. "We suggest it might be to the best advantages of the nation and the Air Force to take [money] that might be [applied] to a strategic nuclear bomber -- which will, one, make a marginal contribution and, two, be captured by START numbers that are driving the U.S. nuclear force down -- take those dollars and put them in a new conventional bomber, which will fulfill the roles and missions as we looked at the future and that the bombers are fulfilling today."

December 16, 2009
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WASHINGTON -- A new, independent report recommends that the United States gradually phase out B-2 and B-52 bomber aircraft from its nuclear deterrent (see GSN, Oct. 1).