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As the Western world is trying to gauge whether Russia’s Vladimir Putin is willing to break the 77-year-long taboo against deploying nuclear weapons, the US has stayed silent about its response—albeit with warnings of “catastrophic” and “severe” consequences.
That’s on purpose.
“US policymakers are wisely and deliberately ambiguous on how they would respond,” said Daryl Kimball, executive director of the Arms Control Association. “There are many different scenarios that could involve nuclear use in that war, each of which would create unique circumstances, for which there is no simple, standard response.”
President Joe Biden warned Thursday the US is trying to find an “off-ramp” for Putin, and worried Russia’s threats to use tactical nuclear weapons are real and could lead to “Armageddon.” But even his statements, made at a fundraiser in New York, didn’t hint at any US actions.
National Security Adviser Jake Sullivan recent warning of “catastrophic consequence” should Russia deploy nuclear weapons is a “pretty clear deterrent threat, although the exact response was not specified, likely for deterrent and political reasons,” said Stacie Pettyjohn, senior fellow and director of the defense program at the Center for a New American Security.
What’s the US nuclear strategy?
It’s one word: deterrence. The 2022 Nuclear Posture Review—the nonclassified version—makes clear that maintaining an effective nuclear deterrent and extended deterrence commitments is a top US priority. The US extends nuclear security guarantees to allies in Europe and Asia in large part as an alternative to countries pursuing independent nuclear capabilities.
“We approach deterrence, arms control, and nonproliferation as mutually reinforcing, complementary elements of an integrated strategy for preserving stability, deterring aggression and escalation, and avoiding arms racing and nuclear war,” Ambassador Bonnie Denise Jenkins, the State Department’s under secretary for arms control and international security said at an August conference reviewing the treaty of nonproliferation of nuclear weapons.
“This nuclear saber-rattling is reckless and irresponsible, and at this stage we do not have any information that would cause us to change our strategic deterrence posture,” Pentagon spokesman Pat Ryder told reporters on Thursday. The US assesses Putin hasn’t reached a decision yet on nuclear weapons use, according to Ryder.
Are there any agreements in place?
On Jan. 3, Russia and the US, as well as China, France, and the UK—the five nuclear weapons states—issued a joint statement on preventing nuclear war and avoiding arms races.
“We affirm that a nuclear war cannot be won and must never be fought. As nuclear use would have far-reaching consequences, we also affirm that nuclear weapons—for as long as they continue to exist—should serve defensive purposes, deter aggression, and prevent war,” the five nations wrote. “We each intend to maintain and further strengthen our national measures to prevent unauthorized or unintended use of nuclear weapons.”
In 2021, Biden extended the New START Treaty with Russia for another five years, which requires Russia and the US to disclose their arsenals of strategic nuclear weapons. Those weapons can be launched on intercontinental ballistic missiles, and from submarines and bomber aircraft. But there isn’t much visibility or any treaty governing tactical nuclear weapons with lower yield and lower capacity—exactly the kind of weapons Putin would be inclined to use in Ukraine.
NATO policy spells out that the fundamental purpose of the alliance’s nuclear capability is to preserve peace, prevent coercion, and deter aggression—which also leaves room for maneuvering without locking any country into a specific response.
But under President Donald Trump in 2019, the US formally withdrew from the 1987 Intermediate-Range Nuclear Forces Treaty that required the US and the Soviet Union to eliminate and permanently forswear all of their nuclear and conventional ground-launched ballistic and cruise missiles with ranges of 500 to 5,500 kilometers. The US argued at the time that it found Russia in “material breach” of the treaty.
What are likely scenarios?
The specific response would depend on exactly the type of nuclear attack Russia executed and what Biden and other allied leaders decide, CNAS’s Pettyjohn explained. “A high-altitude detonation or demonstration shot that doesn’t kill anyone likely would not trigger the same response as a nonstrategic weapon being fired at Ukrainian forces or cities,” she said. “Deterrence is a perceptual phenomenon, and the West does not know exactly how Putin views this situation, or what he sees as a cost that he isn’t willing to bear.”
So the goal is not to be “overly prescriptive,” she added, as the US and NATO need flexibility to determine the best course of action, depending on what Putin might do.
Biden is likely not “seriously considering” nuclear retaliation in response to Russia’s potential use of tactical nuclear weapons against Ukraine, according to Kimball. Even a limited conventional counter-strike against the military bases that launched nuclear weapons could lead to Russian retaliation and wider escalation, Kimball explained.
Putin “likely understands and must be reminded that the actual the use of nuclear weapons would be catastrophic for him, the Kremlin, and for global interests,” he added.
What does one simulation show?
A 2019 simulation from Princeton University’s Program on Science and Global Security shows a plausible step-by-step escalation of nuclear war between the US and Russia that starts in Europe.
“The risk of nuclear war has increased dramatically in the past two years as the United States and Russia have abandoned long-standing nuclear arms control treaties, started to develop new kinds of nuclear weapons, and expanded the circumstances in which they might use nuclear weapons,” according to the program’s website.
Under the simulation, Russia launches a nuclear warning shot from the city of Kaliningrad to halt US-NATO advances. NATO retaliates with a single tactical nuclear air strike. As the nuclear threshold is crossed, fighting escalates to a tactical nuclear war in Europe, with Russia sending 300 nuclear warheads via aircraft and missile, and NATO responding with 180 nuclear warheads shot from aircraft.
The immediate casualty list reaches 2.6 million in more than three hours.
NATO then responds with 600 strategic nuclear warheads shot from the US land and submarine bases, and Russia launches missiles from silos, road vehicles, and submarines. The immediate casualty count is 3.4 million in about 45 minutes.
With the aim of inhibiting the other side’s recovery, Russia and NATO target each other’s 30 most populated cities, using five to 10 warheads depending on population size. Casualties from this move would reach 85.3 million in about 45 minutes. The overall number of immediate dead from the nuclear exchanges would reach 91.5 million, with deaths from nuclear fallout and other long-term effects significantly increasing the casualty number.
Any lessons learned?
“From the past games, we learned that it was difficult to deescalate the situation and achieve the US’s objectives,” Pettyjohn said. “One can always deescalate by capitulating but that is not what the US is searching for.”
“Once nuclear weapons are used—even in a very limited fashion—escalation dynamics are dangerous and hard to predict,” Pettyjohn added.
Putin’s use of even tactical nuclear weapons would lead to the opening “of the last destructive direction in relation to Russia, and there would be no chance for Russia to return to the club of countries, with which at least someone shakes hands,” Ukraine’s Minister of Defense Oleksii Reznikov said, according to Interfax Ukraine.
To contact the reporter on this story: Roxana Tiron in Washington at firstname.lastname@example.org