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– Suzanne DiMaggio
Senior Fellow, Carnegie Endowment for International Peace
April 15, 2019
Pentagon Defends Global-Strike Plan

Wade Boese

A recently unveiled initiative to arm some U.S. submarine-launched ballistic missiles (SLBMs) with conventional warheads has lawmakers wondering whether dangerous misunderstandings and miscalculations could arise with other nuclear powers, particularly Russia. Pentagon officials downplay the possibility, contending that the benefits of the new capability outweigh the potential risks.

The Department of Defense is asking Congress this year for $127 million to start replacing nuclear warheads with conventional warheads on 24 Trident D-5 SLBMs. Within two years, two dozen missiles would be equally dispersed among 12 separate submarines, which means each vessel would carry 22 nuclear-armed and two conventional-armed missiles. The conventional warheads, four per missile, would be either a solid slug or a bundle of rods known as a flachette round, not explosive warheads.

Although the Bush administration revealed its intentions to pursue conventional global-strike capabilities in its December 2001 Nuclear Posture Review, the SLBM option was first detailed in early February as part of the Quadrennial Defense Review. (See ACT, March 2006.) The so-called prompt global-strike concept behind the SLBM conversion seeks to enable the United States to attack a target anywhere in the world with a conventional warhead in less than an hour.

At a March 29 hearing of the Senate Armed Services Strategic Forces Subcommittee, legislators expressed some unease about the SLBM proposal. Subcommittee chairman Jeff Sessions (R-Ala.) and ranking member Bill Nelson (D-Fla.) both questioned whether submarines with mixed loads might cause confusion for other countries about the type of missile fired and its intended target. In such a circumstance, they worried a country might mistakenly conclude that it was under U.S. nuclear attack and potentially retaliate with nuclear weapons.

Assistant Secretary of Defense for International Security Policy Peter Flory said the Pentagon takes this concern “very seriously.” However, he and General James Cartwright, commander of U.S. Strategic Command, minimized the danger of miscalculation. In addition to its traditional mission of exercising operational control over deployed nuclear forces, Strategic Command over the past few years also has been tasked with overseeing the development and fielding of missile defenses and global-strike capabilities.

Flory said that the United States has emergency communication mechanisms, such as hotlines, with Russia and China “for mitigating any potential risk of misperception.” Cartwright and Flory also stated the United States would rely on advance notification measures and military-to-military talks to help alleviate uncertainty. They further asserted the launch and trajectory of a conventional system could be made to appear differently than that of a nuclear missile.

Cartwright also made the case that the United States has a long record of launching non-nuclear missiles without a negative incident. “Since 1968, we’ve launched 433 of these warheads on these missiles without ambiguity through notification processes,” Cartwright testified. The general was referring to SLBM test launches not involving nuclear warheads, a spokesperson from Strategic Command told Arms Control Today April 21.

Claiming that Russia is the sole country with the current capability to detect and respond rapidly to a ballistic missile launch, Flory argued that “the Russians will know very quickly as they have all the way through the Cold War and up to today what the trajectory is and where the impact points will be.”

Still, Russia detected a missile launch near Norway in January 1995 that led Kremlin leaders to be notified that the United States might have initiated a surprise nuclear attack. Moscow did not immediately order a counterattack and, after anxious minutes, eventually determined that the “missile,” which was a scientific rocket, posed no threat.

Flory and Cartwright maintained that proceeding with conventional SLBMs was worthwhile. Cartwright contended such a capability gives the United States an option for dealing with “fleeting targets” that have a high “regret” factor if they are not destroyed, such as unconventional weapons threats, enemy command and control elements, and terrorists. “In many cases, nuclear weapons are not going to be an appropriate choice for those types of targets, and so you want a conventional alternative,” Cartwright said.

SLBMs were selected over ICBMs as the inaugural conventional prompt global-strike option in part because of their greater accuracy and global range. U.S. ICBM fields are in Montana, North Dakota, and Wyoming, limiting the missiles’ reach and increasing possible overflight and miscalculation problems, particularly with Russia.

Corrected online August 29, 2008. See explanation.