THE RISKS of nuclear war are greater than at any time since the Cuban Missile Crisis. Not only is Vladimir Putin threatening to use nuclear weapons to stave off defeat in Ukraine, but the North Korean Government has continued to develop and test both missiles and nuclear warheads.
U.S. President Joe Biden has responded to Putin’s threats with admirable calm so far, playing down the risk that Putin will use nuclear weapons and avoiding any threat of escalation.
Leaks from the U.S. Administration have indicated that the response to a tactical nuclear weapon would be massive but confined to conventional weapons.
Yet the official doctrine of the U.S. would call for the use of nuclear weapons in exactly the situation faced by Putin today: a conventional war going badly.
Unlike Russia and China, the U.S. military maintains the right to a “flexible response” in which nuclear weapons may be used against an adversary who hasn’t used nuclear weapons and doesn’t pose an existential threat to the U.S. itself 
If Putin is threatened with massive retaliation for breaking a supposed taboo on nuclear weapons, the U.S. should commit itself to “no first use” of nuclear weapons. But why hasn’t this happened already?
Throughout the Cold War, U.S. military planning was based on the assumption that the Soviet Union would have a massive advantage in conventional weaponry, most notably because of its tens of thousands of tanks and other armoured vehicles, not to mention millions of artillery shells.
In the scenario favoured by Pentagon planners, these forces would pour the Fulda Gap, on the border between East and West Germany, rapidly overwhelming North Atlantic Treaty Organization (NATO) forces.
Only the use of “tactical” nuclear weapons would even the balance. The term “tactical” might sound moderately comforting, but some of these weapons would have many times the explosive power of the bombs that destroyed Hiroshima and Nagasaki. They would obliterate the advancing forces.
The end of the Cold War shifted the frontier hundreds of kilometres to the east, but the planners found another “gap” to worry about near Suwałki in Poland. And, as Putin rebuilt the crumbling armed forces he had inherited, it seemed that he still had at least 3,000 modern tanks, with another 10,000 in reserve.
But the failed invasion of Ukraine has shown Putin’s army to be a paper tiger. More than half of Russia’s front-line tanks have already been destroyed or captured by Ukraine. Indeed, Russia has been the biggest single supplier of tanks and armoured vehicles to the Ukrainian armed forces.
Meanwhile, the vast reserves turned out to be largely illusory. Thousands of tanks had been left to rust in the open air or pillaged for parts to be sold on the black market. By June, Russia was reduced to deploying ancient T-62 tanks, first produced in the 1960s and then updated in the 1980s. These have already been destroyed in large numbers.
After failing to conquer its near neighbour, there is no prospect that Russia could launch a successful conventional attack on NATO. There is, therefore, no need for tactical nuclear weapons. The same is true of a hypothetical invasion of Taiwan by China.
By adopting a “no first use” policy, the U.S. could greatly reduce the risk of an accidental nuclear war or an unintended process of escalation. Such a policy would certainly face resistance from the U.S. military, which never saw a weapons system it didn’t find essential — as it would from the Republican party.
And the Biden Administration has moved towards a ban on landmines. A “no first use” commitment once made, would be difficult to roll back, even for a future Trump Administration.
fn1. Putin has used annexation as a way of claiming that resisting Russia’s aggression represents an existential threat