In its annual consideration of the defense policy bill this week, the House Armed Services Committee narrowly rejected efforts to permit the Department of Defense to deploy low-yield submarine-launched ballistic missiles, or SLBM. The committee’s decision sets up a likely fight with the Senate later this year — the outcome of which could impact Moscow’s potential use of low-yield nuclear weapons in a future conflict.

To address an important gap in America’s nuclear deterrent, the U.S. should deploy without delay a submarine-launched low-yield nuclear ballistic missile.

In its fiscal 2020 budget request, the Trump administration requested funding to deploy a low-yield SLBM in order to deter Russia’s potential employment of a low-yield nuclear weapon. Gen. John Hyten, commander of U.S. Strategic Command, testified in February 2019 that this capability was “necessary to our strategic deterrence mission and will serve to disabuse any adversary of the mistaken perception they can escalate their way to victory.”

Sometimes characterized as “escalate to de-escalate,” Moscow has developed a war-fighting strategy and doctrine that emphasize the first use (or threat of use) of low-yield tactical nuclear strikes against conventional military targets. Such an approach would aim to coerce the U.S. and its NATO partners into backing down and accepting Moscow’s new gains achieved through aggression. The 2018 Nuclear Posture Review assessed that this Russian nuclear strategy increases the chances of “dangerous miscalculation and escalation.”

The bipartisan National Defense Strategy Commission specifically addressed a scenario in which Moscow used false reports of atrocities against Russian populations in Estonia, Latvia and Lithuania to justify an invasion of these NATO member countries under the guise of a “peacekeeping” mission. In this scenario envisioned by the commission, “As U.S. and NATO forces prepare to respond, Russia declares that strikes against Russian forces in those states will be treated as attacks on Russia itself — implying a potential nuclear response.”

Would Moscow actually use a low-yield nuclear weapon against NATO conventional forces responding to Russian aggression in the Baltics? Facts and prudence do not permit ruling that out. NATO leaders would be forced to decide whether Moscow was engaging in a nuclear bluff. If the fear of Russia’s potential use of a low-yield nuclear weapon prevented a NATO response, Russian President Vladimir Putin would achieve his leading grand strategic goal — the effective end of NATO as a collective-defense alliance.

Yet, if NATO did honor Article V of the North Atlantic Treaty and responded by sending conventional forces to push Russian forces out of NATO territory, Moscow might be tempted to employ low-yield nuclear weapons if it thought it could get away with it. It seems certain that some Russian military planners would assess that the U.S. would not risk global nuclear war by responding to Moscow’s tactical nuclear strike with a high-yield nuclear weapon, thereby increasing the chances Moscow might employ a low-yield attack in the first place.

Such a scenario may seem far-fetched and too horrible to contemplate for many Americans, but a review of Russian nuclear strategy and doctrine makes clear that the Kremlin views nuclear weapons differently. As the Nuclear Posture Review confirms, “Moscow threatens and exercises limited nuclear first use.”

In short, assuming Moscow would not employ low-yield nuclear weapons in this manner — and making defense policy decisions based on that assumption — would be both dangerous and unwarranted.

Critics argue that the deployment of low-yield nuclear weapons on submarines would spark or exacerbate a nuclear arms race. Moscow has already taken tangible steps toward an arms race: The Kremlin began a comprehensive and aggressive modernization of its nuclear arsenal years ago. Today, Russia already possesses a stockpile of up to 2,000 active nonstrategic nuclear weapons.

The question is whether the U.S. will respond appropriately to protect Americans — or unilaterally constrain its response and ignore Russia’s nuclear activities.

Others claim that a low-yield SLBM is unnecessary because the U.S. already has air-deliverable low-yield nuclear capabilities. That argument ignores increasingly advanced Russian air and missile defense capabilities, as well as the distinct challenges a U.S. low-yield SLBM would present to Russian military planners.

Critics also suggest the deployment of a low-yield nuclear weapon on submarines would increase the likelihood of nuclear war. In reality, fielding a low-yield SLBM would allow the U.S. to more reliably respond at the same nuclear escalatory level. Without low-yield SLBMs, the U.S. could be forced to rely on vulnerable low-yield delivery systems, not respond with nuclear weapons at all or use a larger nuclear warhead.

Based on a perceived reluctance of the U.S. to risk global nuclear war, this could lead Moscow to believe that its use of tactical nuclear weapons might not elicit an effective nuclear response by Washington. That belief — and not the deployment of a U.S. low-yield SLBM — represents the greatest risk for increasing the likelihood of nuclear war.

Today, there exists in the U.S. an important bipartisan consensus on the urgent national security need to modernize America’s nuclear triad and the associated command, control and communications systems. This rightly represents, as the Nuclear Posture Review stated, “a top priority” for the United States.

That bipartisan consensus should include ensuring America’s nuclear deterrent leaves our adversaries with no doubt that a low-yield nuclear weapons attack would receive a robust and appropriate response.

Bradley Bowman is senior director for the Center on Military and Political Power at the Foundation for Defense of Democracies, where Andrew Gabel is a research analyst.

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