The legacy of Hiroshima: The bombing of Hiroshima 60 years ago accelerated the end of the second World War. But it also ushered in a new era in world history. Tom Wright explores how the nuclear bomb transformed military thinking with the advent of the terrifying strategic concept of Mutually Assured Destruction
There is little, if anything, as complicated as nuclear strategy.
Curiously, the peaceful end of the Cold War appears to have given rise to a myth that nuclear deterrence was inevitable, simple and stable. This did not appear to be true early in the Cold War. It may very well not be true at all.
When they first appeared on the scene, 60 years ago this week, nuclear weapons overturned millennia of strategic thinking. Previously, one state's military would have to destroy its enemy's forces before it could lay waste to cities and land. Remember, it was only after years of tough fighting that British and American bombers could destroy Japanese and German cities such as Tokyo and Dresden.
The advent of nuclear weapons meant that one state could simply ignore an enemy's army, navy, and air force, and lob missiles over all defences, killing millions of people, before the first shot was even fired across the trenches.
In the 1940s, as now, nobody had ever participated in a nuclear exchange so nobody knew if such a war could be contained or if it would inevitably spiral out of control. Experience became redundant.
Partly for this reason, the Cold War gave pride of place to civilian strategists, from political science, mathematics and economics, rather than the generals and admirals.
The author Fred Kaplan has called these civilians the Wizards of Armageddon.
One wizard, the much maligned Herman Kahn, a pear shaped man of 300 pounds and the model for Stanley Kubrick's Dr Strangelove, famously chastised the air force for trying to treat nuclear weapons like any other bomb by saying that they did not have war plans but "wargasms".
The wizards became preoccupied with how to construct a nuclear doctrine so that nuclear weapons will never have to be used. The answer they came up with is that you must convincingly threaten that you are willing to start one. Only then will the deterrent be credible, a word that was to become central to everything to do with nuclear weapons. Thus was born the central paradox of the nuclear era: for peace, prepare for war.
The problem was that the United States relied upon nuclear weapons to deter the Soviet Union, which enjoyed a large advantage in conventional forces, from invading Western Europe or the rest of the free world. However, it seemed impossible that Nato would respond to a communist takeover of South Korea or Berlin by destroying Soviet cities and have western population centres razed to the ground in retaliation. Such a threat lacked credibility, a weakness the wizards were acutely aware of.
The result was a series of plans for limited nuclear war, located between complete annihilation and surrender. These plans required the construction of tens of thousands of warheads (the aim was to be able to target the enemy's forces even after being hit first) and the nuclear arms race. The point was to make nuclear retaliation easy. As a result, at the height of nuclear rivalry the Soviet Union and the United States had over 30,000 nuclear warheads each.
To use an oft-used metaphor, in its basic form nuclear deterrence resembled a game of chicken where two cars speed towards each other with the chicken being the first to swerve. In such a game there are advantages to feigning recklessness. Indeed the best way to win a game of chicken is to unscrew the steering wheel and wave it out the window, screaming like a madman, demonstrating that you are not only unwilling but also incapable of swerving. Of course, if both sides do this, things can get complicated and messy.
"Thinking the unthinkable", as it became known, was integral to avoiding war but it outraged many. In a review in Scientific American on Kahn's On Thermonuclear War, the book that introduced many of the basic concepts of deterrence, James R Newman wrote: "Is there really a Herman Kahn? It is hard to believe . . . No one could write like this. No one could think like this . . . This is a moral tract on mass murder: how to plan it, how to commit it, how to get away with it, how to justify it."
Newman's distress is understandable and unavoidable not because Kahn was wrong, although a lot of the time he probably was, but because there was and is no right answer to the basic dilemmas posed by nuclear weapons.
On the one hand, in the context of a standoff like the Cold War, it appears that nuclear weapons are less likely to be used the more a state appears to be willing to use them (the converse may also be true). On the other hand, these efforts to avoid nuclear war may dramatically worsen such a conflict if it actually occurs.
Despite all these efforts, it now appears as if deterrence was even more flawed than commonly thought. Recently opened Soviet archives suggest that the USSR came very close to using nuclear weapons during the Cuban Missile Crisis, not because the Kremlin took a decision but because authority had been pre-delegated to officers in the field.
One story has two out of the three required officers on board a Soviet submarine authorizing the use of a nuclear torpedo against a US ship because they mistook depth charges to enforce a blockade for an attack. Robert McNamara, the then secretary of defence, has said that deterrence did not work, the world simply lucked out.
Since the end of the Cold War nuclear strategy has become neglected as Armageddon receded but the problems posed by the bomb have not gone away.
First, the United States is currently struggling with ways to deter and contain rogue states with nuclear weapons. The Bush administration has promised to develop new, smaller nuclear weapons for use against hardened silos in North Korea and Iran. Those who support this decision argue that only the credible prospect that nuclear weapons will be used will be sufficient to deter proliferation. Those who oppose it worry that this move will break the nuclear taboo and allow others to build their own usable nuclear weapons.
Again, the issue revolves around credibility and the consequences of following through.
Second, if deterrence between two states as large, experienced and cautious as the USSR and the USA was fraught with difficulty, matters can only be complicated further when more nuclear states are added to the mix. This is particularly true given that many of the new nuclear powers are likely to be poor and may pay less attention to elaborate safety mechanisms.
Finally, and perhaps most importantly, nuclear weapons may leak out to terrorist organizations that cannot be deterred because they lack a return address and are often willing to give their own life for their cause. This nexus between weapons of mass destruction and non-state actors could provide small organizations with the capacity to inflict mass violence, something that was previously the reserve of the world's most powerful states.
The author Robert Wright has accurately called this the growing lethality of hatred. Were this nexus to occur, it would have revolutionary consequences maybe even more profound than the invention of the bomb.
Tom Wright is a research fellow at Harvard University's Belfer Center for Science and International Affairs