All eyes are on the conventional war unfolding in Ukraine. But a very different kind of conflict looms over the conflict. Before invading, Putin staged nuclear weapons drills around Russia's border with Ukraine. In case anyone missed the point, his speech justifying the invasion reminded listeners that his country remained "one of the most powerful nuclear powers."
Worse, this rant went hand in hand with a sinister warning: "Whoever tries to hinder us, and even more so, to create threats to our country," he declared, would suffer "consequences that you have never encountered in your history." Next came his announcement that Russia's nuclear forces had been put on a "high alert."
Many Western strategists have interpreted all this as a threat to prod the Ukrainians to surrender or intimidate the Europeans.
Whatever his motives, Putin is using nuclear deterrence as cover for a massive conventional military offensive. This is an ominous turn of events. To the extent this has ever worked in the nuclear age, it did so by forcing adversaries to adopt cautious, non-confrontational positions. But understanding how doctrines of deterrence developed during the Cold War underscores the degree to which we are in uncharted waters.
Most accounts of nuclear strategy begin with the U.S. dropping atomic bombs on Japan in 1945. In the weeks and months that followed, a group of scholars at Yale wrote essays on nuclear warfare they collected in a short book titled "The Absolute Weapon."
The most influential piece of the bunch came from military thinker Bernard Brodie. In the space of a few paragraphs, he laid out the mind-bending implications of the bomb for military strategy. His essay is still worth reading.
Brodie pointed out that "if the atomic bomb can be used without fear of substantial retaliation in kind, it will clearly encourage aggression." The only way to counteract this, he argued, was "to make it as certain as possible that the aggressor who uses the bomb will have it used against him."
Writing at the end of the worst war in world history, Brodie acknowledged that "the possibility of irresponsible or desperate men again becoming rulers of powerful states cannot ... be ruled out in the future." But it was possible, he averred, that such leaders and their military supporters could be disabused of the idea "that aggression will be cheap."
Brodie concluded with these oft-quoted lines: "Thus far the chief purpose of our military establishment has been to win wars. From now on its chief purpose must be to avert them. It can have almost no other useful purpose."
The argument found few takers at first. Other doctrines found favor instead. Secretary of State John Foster Dulles, for example, advanced the doctrine of "massive retaliation," where conventional attacks could be met by a disproportionate nuclear response.
Others, like Henry Kissinger, thought there was a space for "limited" nuclear war, where tactical nukes might coexist with conventional weaponry. Still others thought it possible to launch a pre-emptive "first strike" that destroyed an adversary's entire nuclear arsenal.
Brodie had little patience for such thinking. In 1951, he moved to the RAND Corporation, where he expanded the idea first proposed in his seminal essay. Other civilian strategists joined him there: the political scientist Albert Wohlstetter; the economist Thomas Schelling; polymath, game theorist and provocateur Herman Kahn, and many others.
These thinkers began to debate the nuances of nuclear strategy with the fervor of medieval scholastics. RAND was their monastery, and their deliberations gave rise to the rudiments of modern nuclear strategy.
They proceeded as technological advances made a successful first strike increasingly impossible: Newly commissioned submarines could lurk undetected, firing the retaliatory second strike; missiles waiting in subterranean silos could do the same.
These developments nudged these thinkers toward a revolutionary conclusion: If both sides realized that a first strike would inevitably trigger a devastating second strike in return, neither side would pre-emptively use nuclear weapons. Instead, a "stable balance of terror" would prevail. In turn, this would deter conventional conflict as well out of fear it might spiral into a nuclear exchange.
The subtleties of these doctrines defy easy summary, particularly because they beget counterintuitive corollaries. For example, some RAND theorists maintained that government-sponsored efforts to survive a potential nuclear war - building civil defense shelters, for example - were a bad idea, because the Soviets would assume the Americans intended to survive a nuclear exchange. This in turn could be misinterpreted to mean we meant to launch a pre-emptive attack.
All of this might have remained a macabre intellectual exercise, but Secretary of Defense Robert McNamara, himself a devotee of the RAND way, put these ideas into practice in the wake of the Cuban Missile Crisis. They became known as "assured destruction" or, eventually, "mutually assured destruction," or MAD.
This was the basic theory of deterrence that remained operative, with some modifications, until the end of the Cold War. As Brodie anticipated, MAD scrambles conventional understandings of strategic advantage and deterrence.
For example, when it became apparent that the Soviets had developed an impregnable second-strike capacity, McNamara publicly acknowledged this as a welcome development. Why? Because by doing so, the Soviet Union now knew that we knew that they possessed a second-strike option. The balance of terror had been achieved.
This generated an eerie stability in Europe, with a sharply defined line separating two sides, each armed to the teeth with conventional and nuclear weapons. But they would not fight. Instead, the superpowers would fight conventional wars by proxy elsewhere in the world.
In 1981, the nuclear strategist Kenneth Waltz observed: "Never since the Treaty of Westphalia in 1648 ... have great powers enjoyed a longer period of peace than we have known since the Second World War. One can scarcely believe that the presence of nuclear weapons does not greatly help to explain this happy condition."
A decade later, though, the Cold War was over. There was much debate in strategic circles about whether deterrence would work in a messy, multipolar world. Some, like Waltz, believed that it would. "With nuclear weapons," he wrote, "it's been proven without exception that whoever gets nuclear weapons behaves with caution and moderation."
A recent review of nuclear strategy has described this point of view as the "easy deterrence" school of thought. But there is an alternative - and dissenting - theory of nuclear deterrence, one rooted in a recognition that, well, leaders don't always behave rationally.
Albert Wohlstetter, one of the original crew at RAND, put this well back in 1958. He acknowledged that many people, including some of his colleagues, believed that the "stability of the thermonuclear balance ... would make aggression irrational or even insane." But, he argued, "the balance is in fact precarious."
These words are worth remembering as we contemplate Putin's alarming rhetoric. The world no longer operates within the carefully constructed scaffolding of deterrence fashioned during the Cold War. That was already too hazardous by half, leading to a number of close calls.
We now confront a challenge of a different order entirely, where a leader driven by grievance and pride is using nuclear deterrence to fight a land war in Europe. In the process, Putin has turned the old doctrines upside down. What formerly was a means of maintaining the status quo has become a threat to destroy it.
If this continues much longer, the old logic of nuclear deterrence may be gone for good. But the terror? Not so much.
(Stephen Mihm, an associate professor of history at the University of Georgia, is a contributor to Bloomberg Opinion.)
(Vishnu Som is Executive Editor, NDTV 24x7)
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)