It doesn’t take a madman to start a nuclear war

Here’s a gloomy proposition: Eventually, a nuclear exchange is inevitable. The atomic genie was released from the bottle at Hiroshima on Aug. 6, 1945. The city was destroyed, and more than 200,000 civilians were killed, instantly or within a few days, or years later from the effects of radiation.

But the world was not as horrified as we might now imagine. Many were simply relieved that World War II was finally over, and the ghastly carnage at Hiroshima and Nagasaki was quietly folded into the suffering and deaths of millions during the war.

Some, however, recognized that the atomic bomb represented a new order of violence. President Harry Truman called the bomb “destructive beyond anything we have ever had. … So we have got to treat this differently from rifles and cannon and ordinary things like that.”

Nevertheless, as the Cold War developed in the late 1940s, prominent Americans talked openly about using nuclear weapons against the Soviet Union, and in the early 1950s, Truman declined to take the atomic bomb off the table during the Korean War.

Fortunately, nobody pulled the trigger. Books such as “Hiroshima,” John Hersey’s vivid account of the devastation of Aug. 6, fostered a better understanding of the horror of nuclear weapons.

And in October 1962, the world was scared straight by the Cuban Missile Crisis, when the U.S. and the U.S.S.R. came dangerously close to a nuclear exchange.

Thus began three decades of an uneasy nuclear standoff between the two most powerful players, as well as the lesser nuclear powers. Mutually assured destruction — MAD — kept the stopper in the nuclear bottle. And after the Soviet Union collapsed in 1991, we sort of forgot about the bottle.

Now the threat is back. Russian President Vladimir Putin has not been subtle. He warned other nations against interfering in his brutal, unprovoked attack on Ukraine by threatening “such consequences as you have never before experienced in your history.”

Lest anyone misunderstand, on Feb. 27 Mr. Putin put his nuclear forces on high alert. It’s difficult to see why the current level of nuclear tension doesn’t approach that of the Cuban Missile Crisis.

Unfortunately, humankind is not through with war. Any hopes left over from the 1960s that someday we might evolve beyond the instinct to fight — “Suppose they gave a war and nobody came” — have been entirely repudiated by the belligerent decades since.

Further, we have never invented a weapon that we have declined to use. We have tried to outlaw some of the most brutal and inhumane weapons — poison gas, biological agents, napalm and even nuclear weapons — but we’ve never succeeded. Mr. Putin is reportedly using cluster bombs in Ukraine.

No, if we create a weapon, sooner or later, we will use it. Nothing indicates that we will make any special exception for nuclear weapons.

Mutually assured destruction depends heavily on the premise that rational leaders will step away from the brink of the nuclear abyss in the interests of their countries and the survival of the world. The flaw in this questionable theory was the possibility that control of nuclear weapons could fall into the hands of an insane leader.

Now the Ukraine crisis has raised the fear that Mr. Putin has become unstable and therefore more dangerous. Perhaps. But the distinction between a madman and a putatively rational leader who sees his interests in serious jeopardy is irrelevant. Truman, who ordered the attack on Hiroshima, was one of our most rational presidents. A nuclear war is as likely to be sparked by a desperate, cornered leader as by a madman. We cannot depend on Mr. Putin’s mental health to keep us safe from a nuclear exchange.

The war in Ukraine is a showdown between autocracy and a liberal free world. The outcome is much more likely to be determined by force than by diplomacy and sanctions. It would be wonderful if nuclear weapons could be removed from the calculus of force that will stop Mr. Putin. Unfortunately, history suggests otherwise.