After a series of losses on the battlefield in eastern Ukraine, Russian President Vladimir Putin issued an ambiguous yet ominous threat to use a nuclear weapon. “If the territorial integrity of our country is threatened, we will without a doubt use all available means to protect Russia and our people,” he said Wednesday in a nationally televised speech. “This is not a bluff.”
Since he ordered the invasion of Ukraine on Feb. 24, Putin has routinely reminded the world that Moscow’s nuclear arsenal is the world’s largest. He has publicly placed Russia’s nuclear forces on “special combat readiness” alert, held high-profile nuclear drills and issued veiled threats to use a nuclear weapon if any nation gets in the way of his goal to overthrow the government in Kyiv.
All of these moves have thus far appeared to be primarily for show—U.S. intelligence has yet to observe changes in the posture of Russia’s strategic arsenal—but the prospect of the world’s most powerful weapon cannot be disregarded, and Putin’s latest statement appeared to expand the realm of scenarios in which he says he might launch one. The Biden Administration has formed a team of experts to strategize responses if Russia does the unthinkable.
Experts inside and outside the government still believe it’s highly unlikely Putin would ever go nuclear over Ukraine. But the fear is he might, particularly if the Russian invasion continues to run into stiff resistance and debilitating strategic setbacks. Putin could launch a limited nuclear strike, or the demonstration of one, out of desperation, say intelligence officials. Moscow has invested billions of dollars into overhauling its nuclear forces and reshaping its arsenal. At Putin’s order, the military began amassing a wide range of smaller arms with lower explosive yields, called tactical nuclear weapons, designed for use on the battlefield in a “limited nuclear war.”
Read More: Inside the $100 Billion Mission to Modernize America’s Aging Nuclear Missiles
Yet Putin’s Wednesday declaration went a step further than the conditions under which Russia previously said it would use nuclear weapons, outlined in a six-page June 2020 document entitled: “The Basic Principles of the Russian Federation’s State Policy in the Domain of Nuclear Deterrence.” The decree says Russia would go nuclear in response to the use of nuclear weapons or other weapons of mass destruction, and “in the case of aggression against the Russian Federation with the use of conventional weapons, when the very existence of the state is put under threat.” In his national address on Wednesday, Putin said Russia was planning to annex its occupied regions of southern and eastern Ukraine following Kremlin-run referendums to create “republics,” and added he was ready to defend the “territorial integrity” of the occupied territory “by all means.”
A senior Administration official told reporters Wednesday that Putin’s latest round of “playing the nuclear card” is based on a new “legalistic” construct he is presenting: if these “sham” referendums pass, then any attempts by Ukraine to retake those territories will be seen as an attack on Russia itself—thus allowing Moscow to go nuclear under the terms of the 2020 decree.
Speaking at the United Nations General Assembly in New York on Wednesday morning, President Joe Biden said Putin was making “reckless” and “irresponsible” nuclear threats and accused Russia of violating the defining tenets of UN membership in its unprovoked invasion of Ukraine.
Biden has taken various steps to avoid escalating tensions with Russia. He’s postponed an intercontinental ballistic missile test, nixed a plan to provide Ukraine with fighter jets, and has refused to match Putin’s heated rhetoric with threats of his own. Rather than enter the war, he’s opted for a muted, dual-track strategy of providing arms to Ukraine’s military, while pounding Russia’s economy with crippling sanctions. When asked about the potential of Putin using chemical or tactical nuclear weapons during a “60 Minutes” interview on Sept. 18, Biden replied: “Don’t. Don’t. Don’t. You will change the face of war unlike anything since World War II.”
The threat of tactical nukes
Although remote, Pentagon and intelligence officials believe the most likely nuclear scenario would be if, faced with overwhelming conventional military force that pushed the Ukraine advance into Russian territory, Putin could reach for a smaller tactical nuke. His goal would be to intimidate the Ukrainian government and force the U.S. and its allies to back away from the conflict if nuclear holocaust loomed above it. No one wins an all-out nuclear war, Russia’s theory holds, but a single smaller detonation might be devastating enough to bring an adversary like Ukraine to its knees—and scary enough to deter the U.S. from launching a tit-for-tat response that could kill thousands, if not millions.
The nuclear bombs that the U.S. dropped on Hiroshima and Nagasaki in 1945 produced the equivalent of 15,000 tons to 25,000 tons of TNT. A tactical nuclear weapon’s detonation power can equal these amounts or just a fraction, 1,000 tons of TNT or less. Putin has invested heavily in these weapons and boasts an estimated 2,000 tactical nukes featuring varying yields and delivery platforms, according to U.S. intelligence estimates. Russia’s tactical nuclear arsenal, including anti-ship missiles, torpedoes, and cruise missiles, have been updated with greater accuracy, longer ranges, and lower yields to suit their potential war fighting role, according to U.S. assessments.
Not since the Cold War has the specter of nuclear weapons loomed so large. From the 1960s through the 1980s, the U.S. and the Soviet Union each arrayed tens of thousands of nuclear warheads targeting every major city and industrial asset inside one another’s countries. What kept them in check—and what continues to—is the expectation that if one side launched a nuclear strike, it will have to deal with the devastating repercussions. The theory, known as mutually assured destruction (MAD), is what military planners have banked upon since the dawn of the atomic age.
The two sides gradually drew down the numbers of weapons through various treaties designed to limit the spread of nuclear arms. The current linchpin agreement, called the New Strategic Arms Reduction Treaty (START), limits the U.S. and Russia each to 1,550 deployed nuclear warheads—strategic weapons deployed in missile silos, submarines, and intercontinental bombers. However, the treaty does not apply to smaller “nonstrategic” warheads. Both nations are free to amass as many tactical weapons as they desire.
The U.S., for its part, has largely abandoned developing and deploying these tactical weapons after President George H. W. Bush issued an order to do so in September 1991. The military disassembled around 5,000 weapons, including nuclear landmines, nuclear depth charges, and nuclear artillery shells, primarily positioned around Europe. After the purge, the only tactical weapons left behind were the roughly 200 B61 nuclear bombs that the U.S. has deployed in five NATO nations stretching from the Netherlands to Turkey. Even though the weapons are mostly symbolic to alliance unity, Russia has long requested the B61s’ removal from the European continent—a demand reiterated as the Ukraine crisis has worsened. “Having a NATO nuclear capability, however small, keeps all NATO members enmeshed in and committed to the nuclear deterrence mission,” says Rose Gottemoeller, former deputy secretary general of NATO and retired U.S. diplomat.
The crisis raises questions about the future of U.S.-Russia relations and prospects for continued nuclear arms reductions. The U.S. suspended bilateral engagements arms control talks with Russia after its invasion of Ukraine. Even at the darkest moments of the Cold War, the United States and Soviet Union would hold diplomatic negotiations about nuclear arms. The superpowers identified certain weapons deemed mutually menacing, and then worked to eliminate the threat.
Thomas Graham, a retired U.S. ambassador who helped negotiate every international arms control and non-proliferation agreement between 1970 and 1997, says the world is headed toward a complete “unraveling” of the many safe-guards that kept nuclear war at bay. While Putin’s saber-rattling could be simply dismissed as an intimidation tactic, the threat is serious enough that it can’t be ignored. “If he gets back up against the wall, which he will, then I think we have a problem if we press him,” Graham says. “He could do anything.”
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Write to W.J. Hennigan/Honolulu, HI at william.hennigan@time.com