The nuclear age dawned at Alamogordo, New Mexico, on July 16, 1945 when a twenty-two kiloton device was tested. Robert Oppenheimer, the chief scientist of the project, prophetically declared, “I am become Death, the shatterer of Worlds.” The world got a further sample of what was potentially in store for them on August 6 and again on August 9, when the American air force bombed Hiroshima and Nagasaki. The final act of this drama was played out on August 29, 1949 when the Soviets responded to the Trinity test with their own First Lightning. The stage was now set for the defining characteristic of the global balance of power for the duration of the Cold War.

The invention of nuclear weapons and their proliferation has fundamentally altered not only balances of power in the world but also the very nature of such balances. The predominant debate in the field is that between Kenneth Waltz and Scott Sagan: Waltz has published a series of books advocating the spread of nuclear weapons while Sagan has been equally prolific in demanding the end of nuclearisation. A combined publication, The Spread of Nuclear Weapons, is a very accessible volume that presents the positions of both scholars and their responses to each other in four essays. Sagan, opposed to weaponisation, has suggested a three-fold model explaining nuclear acquisition: a security or neorealist model, which argues that states build weapons for security and because their rivals do, a domestic politics model, which sees nuclear weapons development as the result of manoeuvres by politicians seeking political points and by institutions aiming to retain their power and centrality to government, and a norms model, which argues that weapons acquisition, or restraint in weapons development, provides an important normative symbol of the state’s modernity and identity. Waltz, instead, supports the proliferation of nuclear weapons in certain circumstances. For our purposes, Waltz’s arguments summarise the essence of the nuclear balance of power and how and why the world will never be as it was before 1945.

Waltz argues that with more nuclear powers, flexibility of alliances keeps relations of friendship and enmity fluid and makes everyone’s estimate of the present and future relation of forces uncertain. In a bipolar world, the threats are clearer, whereas in a multipolar world, who is a danger to whom, and who can be expected to deal with threats and problems, are matters of uncertainty. Dangers are diffused, responsibilities blurred, and definitions of vital interest easily obscured. In the nuclear age, a state becomes a great power not by military or economic capability alone but by combining political, social, economic, military, and geo­graphic assets in more effective ways than other states can. In the old days weaker powers could enter into alliances to increase their power. Today, that is not possible. First, nuclear forces do not add up. The technology of warheads, of delivery vehicles, of detection and surveillance devices, of command and control systems, count more than the size of forces. Therefore, combining separate national forces does not lower a nation’s threat perception. Waltz agrees with de Gaulle’s observation that nuclear weapons make alli­ances obsolete.

Waltz gives multiple reasons why states would want nuclear weapons despite the high cost. Many of his observations match the reasons stated by nuclear powers for their programs. Waltz argues that states would want to exercise the nuclear option 1) to counter the nuclear threat from another state (Soviet Union), 2) lack of trust in one’s ally to retaliate in case of nuclear strike (United Kingdom, France), 3) if its adversaries have nuclear weapons (China), 4) in fear of its adversary’s future proclivities, (India, Pakistan), 5) as a cheaper method to counter vastly superior conventional forces (Israel), or 6) for offensive purposes (North Korea). As Waltz notes, self-help is the principle of action in an anarchic order, and the most important way in which states must help themselves is by providing for their own security. The logic behind nuclear deterrence is two-fold: 1) total annihilation in the Soviet or American mould, also known as Mutual Assured Destruction (MAD), or 2) damage that more than cancels your gain, termed Mutually Unacceptable Damage (MUD). In the second school of thought, nuclear war is possible because most weapons used will be of sub-kiloton yield, not the city busters of the previous generation.

The nuclear balance of power is quite different from traditional balance of powers. The equilibrium achieved by Metternich after the Napoleonic Wars maintained peace for the entire long nineteenth century but was easily broken once empire building created enough momentum. One state could challenge another and escape the consequences to an extent. German adventurism in Schleswig-Holstein and at Königgrätz, the involvement of the Great Powers in Crimea, the Agadir Crisis, and other such flashpoints were possible only because the crises occurred far away from home territory and were rarely deemed serious enough to escalate into direct global conflict between two Great Powers. Thus, Great Britain and Russia were able to openly challenge each other in Afghanistan and the Crimea and contain a limited conflict. In the nuclear balance of power, with the advent of missile technology and long-range strike aircraft, the danger was that any conflict would at once escalate into total global war. As a result, the United States made great efforts to conceal their clash with Soviet pilots during the Korean War; an over-zealous anti-communist public might force the government into a precarious position internationally. Further, even if war were to break out between the Great Powers in the nineteenth century, mobilisation of troops and their deployment would take weeks. Barbara Tuchman’s The Guns of August amply illustrate the problems with an army moving on horseback and trains. In the nuclear age, a MIRV coming in over the pole would give about six – ten minutes of early warning to the victim of the attack, after which the devastation would be absolute. Even the carnage of World War I was the result of years of bitter fighting in a stagnant battlefield. In a nuclear war, the whole country is an immediate target for annihilation. Particularly in a world of nuclear alliances, the whole globe is a legitimate mark for utter destruction. Waltz argues that with such high stakes involved, states would be more careful to avoid conflict. If the cost of winning is prohibitive, states would not dare to gamble on war. As an example, Waltz compares the Kargil conflict to the India-Pakistan War of 1965. The former was far more restricted, because of the threat of escalation to nuclear proportions Waltz opines, than the latter which was quite lethal in terms of human and material costs. After the 1998 tests, India and Pakistan are more cautious in their cross-border tit-for-tat behaviour.

Another change from an older balance of power is that even as late as 1945, the Soviet Union wanted a land buffer between itself and Germany. In the world of Metternich, states could trade space for security. As Napoleon’s Grande Armée learned in 1812, the additional time required for his troops to catch up with the retreating Russians was enough for them to reorganise and counterattack. In the nuclear world, territorial depth is meaningless. Even with primitive delivery systems, space is not an issue for the aggressor. American or NATO missiles would face little difficulty by way of supply lines or weather on their way to their targets deep in the Soviet Union. Territorial depth is concern of conventionally armed states. For example, Chaim Herzog’s War of Atonement describes the problems Israel faced in 1973 because it lacked the depth to stretch out enemy lines and counterattack. As a result, it is rumoured that Israel considered a nuclear strike in the first two days of the Yom Kippur War.

Proponents of nuclear deterrence also argue that had nuclear weapons been incapable of posing a threat, they could not have prevented war between the two superpower blocks. Given the relatively low level of conflict between the Soviet Union and the United States during the Cold War, they have obviously been successful in performing their task. The nuclear truth is, as Waltz says, “if a part of a force is invulnerable, then the whole force in invulnerable.” This is the security provided by the mushroom cloud that has contributed much to world order. In previous eras, England and France could be at war in Africa, at peace in Europe, and allies in the Crimea against the Russians. In the post-1945 world, the options available are more polarised. China may support Pakistan against India or fund separatist groups, but it will hesitate to use its own troops. China’s eschewal of the opportunities the South Asian Crisis of 1971 provided to extend its strategic territorial interests in the Indian Himalayas because of the risk of Soviet reprisal, or the US attempt to pressure India by sending in the USS Enterprise showed the role of deterrence and the limitations nuclear weapons put on the actors. Such delicate tiptoeing was not seen in July 1914.

A key difference between a balance of power enforced by nuclear weapons and Metternich’s Europe is that the former is purely defensive while the latter is aggressive. In the world of Metternich, states came together to promise not to attack each other, at least refrain from conflict within Europe. The world order reined in their aggressive instinct and directed it towards weaker states with whom conflict would not have serious consequences. In the nuclear world, atomic incineration is a defensive threat—states promise retaliation if attacked rather than nonaggression. This seemingly minor difference is quite a severe change in mentalités. Michael Mandelbaum’s The Nuclear Question exposes this change in the new world order more succinctly: because nuclear war is unthinkable, wars are fought by proxy and guerrilla warfare is the new trend. The Soviets and Americans could thus engage in Third World, non-critical battlegrounds such as Asia and Africa in much the same way as they might have in the nineteenth century. In a paradoxical way, nuclear weapons have reintroduced limited war into the world politic as it used to be before the two World Wars of the twentieth century, and indeed, even the Napoleonic Wars. Given the lower risks in such conflicts, Mandelbaum calls it the “best of all possible nuclear worlds.” The primary reason Mandelbaum thinks so is because, as Bernard Brodie explains in The Absolute Weapon and also Strategy in the Missile Age, the chief purpose of the military establishment until then had been to win wars. With the advent of the nuclear age, the chief purpose has shifted to avoiding them. The question post-1945 is not of attack but of retaliatory defence; the risks involved in a war with a nuclear state are too steep to be considered. In the previous century, or among non-nuclear states this century, the main question in any military adventure is of the success of the attack. Minor losses can be acceptable, whereas in a nuclear war, a minor loss would still mean millions of lives. In Waltz’s formulation, nations acquire nuclear weapons not to menace their neighbours but to protect themselves, contrary toSagan’s view. The spread of nuclear weapons is a greater testament to the domino theory than the spread of communism. American monopoly of the atom provided the incentive to the Soviets to test their own device. The American and Soviet threat propelled the Chinese to get their own bomb, which in turn forced India to acquire its device and in turn, Pakistan. In the case of the United Kingdom and France, the lack of faith that the United States would risk its own destruction to save Europe motivated both nations to develop an indigenous program. And to the governments of North Korea and Iran, the primary threat is the United States.

An innovation in Realist thought has been Stephen Walt’s modification of the traditional balance of power theory. Walt argues that this theory has not borne out during the Cold War because, according to the theory, states should align themselves against a rising power as European states did before 1945. However, during the Cold War, the United States, a superpower whose military and economic capabilities increased exponentially in relation to other states, was able to ally itself with a host of countries. Walt proposes instead that the theory address the balance of threat. States align themselves against perceived threats rather than powers. Thus, Europe worked in close cooperation with the United States against the Soviets because the European nation-states worried about Soviet intentions and not US power. This, development, as Walt points out, is pretty recent. British history, for example, is replete with instances of fighting with the weak against the strong until the Cold War. In fact, other Great Powers behaved in much the same manner, although perhaps with less fickle-mindedness than the British.

Yet another change from the older world order as John Mearsheimer observes in The Tragedy of Great Power Politics, is that nuclear weapon states will be off-limits to international pressure, threats of attack, or covert operations—an attractive proposition. In previous eras, any state, however powerful, was subject to an international coalition of forces acting against it. Napoleonic France, for example, withstood six coalitions before finally being defeated. However, in the nuclear system, the nuclear haves are a law unto themselves, most of them having not only tremendous destructive capacity but also permanent seats and vetoes in the Security Council, a mark of their strength. This situation was described by Krishna Menon as “nuclear apartheid.” The more nuclear nations, the less leverage the superpowers have. According to Robert Jervis, even allies who procure nuclear weapons will start to distance themselves from their previous patrons. If proliferation were to spread to, for example, Japan, Germany, and South Korea, they will experience greater flexibility in their foreign policy as it means less American or Soviet leverage with them. The French example is also a particularly poignant example of this. Thus, nuclear weapons allow a state a shortcut to Great Power status—even if it is economically and conventionally weak, other states will not be able to dictate terms to it. The latent power accrued by a state by crossing the nuclear Rubicon is far higher than any other invention in history. Ultimately, no amount of military might allows a country to wish away the bomb. Whether or not nuclear weapons make the world a more dangerous place, they certainly make it a more humbling one, and their spread only narrows the options of the five declared nuclear powers under the Non-Proliferation Treaty.