Here’s how to think about the unthinkable.
Vladimir Putin looks on during the Victory Day military parade in Moscow, May 9. | Mikhail Metzel/Sputnik via AP
By Gregg Herken, Avner Cohen and George M. Moore
Gregg Herken is an emeritus professor of American diplomatic history at the University of California, and author of Brotherhood of the Bomb.
Avner Cohen is a professor of nonproliferation studies at the Middlebury Institute of International Studies at Monterey and the author of Israel and the Bomb.
George M. Moore, PhD, is scientist-in-residence at the Middlebury Institute of International Studies in Monterey.
We know that Russian President Vladimir Putin is thinking about using nuclear weapons. He has twice warned the West not to intervene in Ukraine or face “consequences that you have never encountered in your history.” Recently, Moscow again threatened “unpredictable consequences” if the U.S. continued sending advanced armaments to Ukraine. CIA Director William Burns has said that “none of us can take lightly” the prospect that Putin might resort to the use of tactical nuclear weapons.
While any use of a nuclear weapon is unthinkable to most of the world, under current Russian military doctrine — usually described in shorthand as “escalate to deescalate” — Putin could choose a nuclear “demonstration” as a warning to halt further American military aid to the Ukrainians. In other words, for the Russian leader, detonation of a tactical nuclear weapon by Russia is entirely thinkable. And so the West needs to do some thinking, too.
Tactical nuclear weapons are often called “battlefield” or “theater” weapons to distinguish them from much more powerful strategic nuclear weapons, but they are far more destructive than conventional weapons. During the Cold War, tactical nuclear weapons had yields ranging from tens or hundreds of tons of TNT to thousands of tons. These weapons came in many forms: gravity bombs, short-range missile warheads, anti-aircraft missiles, air-to-air and air-to ground missiles, anti-ship and anti-submarine torpedoes and even demolition devices or mines. Reportedly, the smallest tactical weapon in the Russian nuclear arsenal has a yield of about one-third the size of Hiroshima or Nagasaki bombs, or equivalent to about 5,000 tons of TNT.
There are a few ways that such a tactical nuclear weapon could be used to fire the kind of “warning shot” envisioned in Russian military doctrine. These options come with increasing degrees of risk for the U.S., Ukraine and its allies, and for Russia.
Here are three scenarios.
Least provocative would be Putin’s resumption of above-ground nuclear testing — by detonating a low-yield nuclear warhead high above Novaya Zemlya, the old Soviet test site in the Arctic, for example. While both the actual damage on the ground and radioactive fallout would be negligible, the psychological effect could be enormous: It would be the first nuclear explosion by a superpower since nuclear testing ended in 1992, and the first bomb detonated in the atmosphere by either the U.S. or Russia after such tests were outlawed by treaty in 1963. It would also be a potent reminder that Putin has tactical nuclear weapons in abundance — about 2,000 by last count — and is prepared to use them.
A more provocative demonstration would be an ultra-high-altitude explosion of a more powerful weapon over Ukraine itself. In a 1962 test, the U.S. detonated a 1.4-megaton H-bomb in the mid-Pacific, 250 miles above the Earth. The resulting electromagnetic pulse unexpectedly knocked out streetlights and disrupted telephone service in Hawaii, 900 miles distant. A similarly powerful explosion above Kyiv would not only be visually spectacular but would likely plunge the capital into prolonged darkness and silence by shorting out computers, cellphones and other electronics. EMP effects might also extend into NATO member countries. But the extent of damage from the pulse is unpredictable, and Russian communications could also be affected.
Most dangerous — and, for that reason, perhaps least likely — would be using a tactical nuclear weapon to achieve a concrete military objective such as disrupting the delivery of weapons to Ukrainians fighting in a city like Mariupol. Alternatively, Putin might detonate a tactical nuclear warhead against military or logistics targets in sparsely populated western Ukraine — in the agricultural lands between Lviv and Kyiv, for instance — after warning people in the target area to evacuate. But even the smallest nuclear weapon would set fires over a wide area if detonated in the air. Depending on the height of the explosion, it could also spread lingering radioactive fallout, possibly extending into NATO member countries and Russia itself.
If, instead of a demonstration in a remote area, Putin were to attack a Ukrainian city with a weapon one-third the Hiroshima yield, the resulting casualties and destruction of property could approach that seen in Japan, since the corresponding radii of damage would be about 70 percent of that seen in those atomic bombings.
While none of the above scenarios is currently likely, neither are they far-fetched. Barring scenarios of an imminent Russian defeat, another humiliation like the loss of the Russian flagship Moskva or growing domestic discontent in Russia at a stalemated war — Putin has no logical reason to initiate the use of nuclear weapons.
But wars are very unpredictable, and there are ample precedents in history where a nuclear demonstration has been considered, beginning with the United States.
In May 1945, weeks before the successful test of the first atomic bomb in New Mexico, former President Harry Truman’s advisers considered, briefly, the option of a harmless but spectacular demonstration of the revolutionary new weapon as an alternative to its military use, in hopes of compelling Japan to surrender. For practical reasons — there were too few bombs in the U.S. nuclear arsenal, and some feared a dud — the demonstration option was never presented to Truman.
But the warning shot idea would surface again and be taken more seriously. During the 1961 Berlin crisis, former President John Kennedy was presented with the option of firing a nuclear-tipped missile at Novaya Zemlya to show American resolve. Israel has also considered a nuclear demonstration; prior to the Six-Day War, in May 1967, Shimon Peres proposed detonating a nuclear device over the Sinai desert to head off the conflict. Six years later, the Israelis again briefly entertained the notion of a high-altitude nuclear warning shot to force an end to 1973’s Yom Kippur War. In 1981, with the Cold War again heating up, Secretary of State Alexander Haig — a former NATO supreme allied commander — let slip that “there are contingency plans in the NATO doctrine to fire a nuclear weapon for demonstrative purposes …”
There is little doubt that a nuclear demonstration is an option that has been considered in the Kremlin. This opens the question of what would be the best U.S. or NATO response. It’s our view that if Putin fires a nuclear warning shot in the Ukraine war, President Joe Biden should resist pressure to respond in kind and avoid any options that could lead to an escalating nuclear exchange. Instead, the president should rally the nations of the world in a universal condemnation of Putin for breaking the nuclear taboo and taking the most dangerous first step toward a nuclear war. The U.S. and NATO could also respond by use of non-kinetic means like cyber warfare. For Biden, regardless of what Putin decides, engaging Russian forces in direct combat should only be a last resort.
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