For much of the 46-year Cold War, many of the West’s most gifted strategists focused their talents on how to prevent the two nuclear superpowers from engaging in a war that could destroy them both — and perhaps the rest of the human race along with them. With the Soviet Union’s collapse in 1991, the threat of nuclear Armageddon receded dramatically and the First Nuclear Age drew to a close.
The world is far different today. On the one hand, both the United States and Russia have far smaller nuclear arsenals than they did at the Cold War’s end. The New Strategic Arms Reduction Treaty (START) limits each country to no more than 1,550 deployed strategic nuclear warheads. At the same time, new nuclear powers have emerged. These developments have introduced a shift from the bipolar Cold War nuclear competition, to an increasingly multipolar competition among nuclear powers and the onset of the Second Nuclear Age.
Yet this new age has not yet produced the foundational analyses that guided policymakers through the First Nuclear Age. Perhaps it is because the Second Nuclear Age appears so much more complex than the first. Or maybe it is because the Second Nuclear Age lacks the immediate existential danger posed by the Soviet Union. Or it might be that in the current age the best analytic talent has been devoted primarily to reducing the number of nuclear players (nonproliferation) and number of weapons (arms control and disarmament), rather than the consequences of such efforts falling short of success.
Scenario-based planning offers one way to explore the contours of the Second Nuclear Age and understand its implications for U.S. interests. For instance, how might the United States respond in a crisis to a Russian threat to employ nuclear weapons in line with its doctrine to “escalate to deescalate” a conflict? Alternatively, assume the recent agreement curbing Iran’s nuclear program fails to prevent Iran from clandestinely acquiring nuclear weapons (or acquiring them after the agreement expires). What can the United States then do to prevent an Israel–Iran crisis from going nuclear? How much more complicated does such a crisis become if a nuclear Iran prompts other Middle Eastern countries, such as Saudi Arabia, to acquire a nuclear capability as well? What might happen if North Korea uses its limited arsenal in a last ditch effort to stave off regime collapse? And finally, how might a long-term, multipolar nuclear competition between the United States, Russia, and China play out?
From scenarios such as these, four themes emerge: the shift from bipolar to multipolar strategic competition; the importance of non-nuclear strategic weapons in assessing the strategic balance; challenges facing countries with small nuclear arsenals; and new sources of crisis instability.
First, nuclear proliferation, and the potential expansion of China’s nuclear arsenal in particular, suggest that the Second Nuclear Age strategic competition will be increasingly multipolar. This competition will exist within the kind of fluid and dynamic international system not seen since before World War II. Establishing a stable strategic balance becomes much more complicated in a fluid international system where the nuclear powers can quickly shift into new alliances and partnerships, and where more countries can acquire nuclear weapons. For instance, consider how the addition of even one nuclear power, such as Saudi Arabia, to an Iran–Israel competition could greatly complicate efforts to maintain crisis stability. In this case, having multiple countries in close geographic proximity places enormous stress on early warning and command-and-control systems.
Additionally, military-technical advances over the past few decades have increased the importance of non-nuclear weapons (such as cyber weapons, conventional precision-strike forces, and advanced missile defenses), enabling what some call prompt conventional global precision strike. This provides the ability to utilize conventional weapons in place of nuclear weapons for some strategic missions. To the extent such forces can substitute for nuclear weapons, it will give technically advanced non-nuclear powers like Germany and Japan the ability to exert a significant effect on the strategic competition. And if the nuclear arsenals of the major powers continue to shrink, the ability of minor nuclear powers to influence the competition will likely grow as well. Put another way, the Cold War “nuclear balance” has evolved into a broader “strategic balance.”
The fielding of advanced air and missile defenses may incentivize minor nuclear powers to develop novel nuclear doctrines. For instance, consider countries such as North Korea that have a far larger inventory of ballistic missiles with only a handful of nuclear weapons. Given this reality, Pyongyang might employ its arsenal using “haystack” tactics. A “haystack” attack involves large missile salvos in which only a few missiles are armed with nuclear warheads. Since the defender cannot readily distinguish between nuclear-armed missiles and decoys, it must attempt to intercept all missiles. In so doing, the attacker can increase the likelihood that a nuclear weapon will reach its target by saturating the defenses.
Finally, if only for the growing number of nuclear powers, the world may experience more nuclear crises in the coming decades than during the First Nuclear Age. Of even greater concern, crisis stability, or the disincentive to use nuclear weapons, will likely be less sturdy than before. For instance, limitations in smaller nuclear powers’ early warning and command-and-control systems might result in their nuclear forces operating on a hair-trigger alert, or with their leaders pre-delegating release authority to protect against a decapitating enemy first strike. It may also force smaller countries to adopt a destabilizing “launch on warning” posture, fearing that otherwise, adversaries, particularly advanced adversaries, may feel capable of striking first without fear of successful nuclear retaliation. Moreover, limited or ineffective early warning systems could complicate the attribution problem. When confronted by multiple adversaries, a country subjected to attack may not be able to determine promptly the source, restricting its ability to retaliate with confidence against the aggressor, thus undermining deterrence.
These themes that help define the Second Nuclear Age have three major implications for U.S. policy. They identify potential gaps in the United States’ strategic arsenal, highlight challenges to extended deterrence, and suggest that efforts towards strategic arms control should consider non-nuclear weapons as well.
It follows that if geopolitical and military-technical changes require us to rethink in fundamental ways our view of strategic warfare, so too must we rethink how this military competition might best be regulated through diplomacy in the form of arms control. Here one might compare the shift from the First to the Second Nuclear Age to the change in the naval competition in the first two decades of the 20th century. Germany and Great Britain were engaging in a furious race focused on building Dreadnought-type battleships prior to World War I. After the war, in 1922, the principal naval powers signed the Washington Naval Treaty to restrain the ongoing multipolar maritime competition. The treaty, however, covered not only the traditional capital ship — the battleship — but also newly emerging vessels like aircraft carriers. Just as the Washington Naval Treaty had to address a multipolar competition and broaden its efforts to include new capabilities affecting the competition, the same may prove true with arms control efforts in the Second Nuclear Age.
Thomas Schelling once lamented that it took 20 years after the dawn of the nuclear age for strategists and policymakers to think through the implications of nuclear weapons. If we mark the advent of the Second Nuclear Age as the point the Soviet Union collapsed and the United States introduced precision warfare, then we are a quarter-century along in this new era without having developed a comparable understanding of nuclear weapons. Whatever the reason for this benign neglect, the existing and prospective challenges posed by the Second Nuclear Age are sobering. If the United States seeks to preserve the nuclear taboo, it ignores them at its peril.