Israel has had an arsenal of nuclear weapons since the late 1960s, and its current inventory is estimated at between 100 and 200 warheads. Some of these weapons will eventually be, or have already been, placed on Israel's missile-carrying submarines, making them virtually impervious to preemptive military attack. They are or soon will be Israel's invulnerable nuclear deterrent.

Yet, hardly a day goes by without some Israeli official, journalist or lobbyist expressing apocalyptic warnings about Iran's nuclear program. Iran, a state party to the Nuclear Nonproliferation Treaty (NPT), is in technical violation of some of its treaty obligations, but its program is still under international inspection by the International Atomic Energy Agency (IAEA). Israel never signed the NPT and thus is not under any international inspection regime.

The tacit assumption behind the apocalyptic pronouncements is that Iran will not only make nuclear weapons, but will use them to destroy Israel shortly thereafter. This amounts to assuming that Iran's leaders are insane. That is, Israel's deterrent notwithstanding, the Iranian clerics' hatred of Israel is so intense that in order to destroy it they would launch a nuclear attack that would kill not only Jews but also up to 1.5 million Muslims living in Israel, as well as triggering an Israeli nuclear counterattack. An Israeli nuclear counterattack, which Iran could not prevent, would turn back the clock on Iran's development for many decades and reduce its leaders to radioactive dust. There is no evidence to suggest that the ruling clerics are so disposed. Some have speculated that Iran might make nuclear weapons and transfer some of them to third parties, e.g. terrorist organizations, for use against Israel. But no country that provides nuclear weapons to a third party can be sure that the transfer will be perfectly secure from discovery or that the weapons will be used as intended. A nuclear attack on Israel using a weapon originating in Iran would undoubtedly be treated as if it came from Tehran, again resulting in Iran's utter destruction.

Interest in nuclear disarmament has grown rapidly in recent years. Starting with the 2007 Wall Street Journal article by four former U.S. statesmen-George Shultz, Henry Kissinger, William Perry, and Sam Nunn-and followed by endorsements from similar sets of former leaders from the United Kingdom, Germany, Poland, Australia, and Italy, the support for global nuclear disarmament has spread. The Japanese and Australian governments announced the creation of the International Commission on Nuclear Non-Proliferation and Disarmament in June 2008. Both Senators John McCain and Barack Obama explicitly supported the vision of a world free of nuclear weapons during the 2008 election campaign. In April 2009, at the London Summit, President Barack Obama and President Dmitri Medvedev called for pragmatic U.S. and Russian steps toward nuclear disarmament, and President Obama then dramatically reaffirmed "clearly and with conviction America's commitment to seek the peace and security of a world without nuclear weapons" in his speech in Prague.

There is a simple explanation for these statements supporting nuclear disarmament: all states that have joined the Nuclear Non-Proliferation Treaty (NPT) are committed "to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament." In the United States, moreover, under Clause 2 of Article 6 of the Constitution, a treaty commitment is "the supreme Law of the Land." To af1/2rm the U.S. commitment to seek a world without nuclear weapons is therefore simply promising that the U.S. government will follow U.S. law.

A closer reading of these various declarations, however, reveals both the complexity of motives and the multiplicity of fears behind the current surge in support of nuclear disarmament. Some declarations emphasize concerns that the current behavior of nuclear-weapons states (NWS) signals to non-nuclear-weapons states (NNWS) that they, too, will need nuclear weapons in the future to meet their national security requirements. Other disarmament advocates stress the growth of global terrorism and the need to reduce the number of weapons and the amount of fissile material that could be stolen or sold to terrorist groups. Some argue that the risk of nuclear weapons accidents or launching nuclear missiles on false warning cannot be entirely eliminated, despite sustained efforts to do so, and thus believe that nuclear deterrence will inevitably fail over time, especially if large arsenals are maintained and new nuclear states, with weak command-and- control systems, emerge.

Perhaps the most widespread motivation for disarmament is the belief that future progress by the NWS to disarm will strongly influence the future willingness of the NNWS to stay within the NPT. If this is true, then the choice we face for the future is not between the current nuclear order of eight or nine NWS and a nuclear-weapons- free world. Rather, the choice we face is between moving toward a nuclear- weapons-free world or, to borrow Henry Rowen's phrase, "moving toward life in a nuclear armed crowd."

There are, of course, many critics of the nuclear disarmament vision. Some critics focus on the problems of how to prevent nuclear weapons "breakout" scenarios in a future world in which many more countries are "latent" NWS because of the spread of uranium enrichment and plutonium reprocessing capabilities to meet the global demand for fuel for nuclear power reactors. Others have expressed fears that deep nuclear arms reductions will inadvertently lead to nuclear proliferation by encouraging U.S. allies currently living under "the U.S. nuclear umbrella" of extended deterrence to pursue their own nuclear weapons for national security reasons. Other critics worry about the "instability of small numbers" problem, fearing that conventional wars would break out in a nuclear disarmed world, and that this risks a rapid nuclear rearmament race by former NWS that would lead to nuclear first use and victory by the more prepared government.

Some critics of disarmament falsely complain about nonexistent proposals for U.S. unilateral disarmament. Frank Gaffney, for example, asserts that there has been "a 17 year-long unilateral U.S. nuclear freeze" and claims that President Obama "stands to transform the ‘world's only superpower' into a nuclear impotent." More serious critics focus on those problems-the growth and potential breakout of latent NWS, the future of extended deterrence, the enforcement of disarmament, and the potential instability of small numbers-that concern mutual nuclear disarmament. These legitimate concerns must be addressed in a credible manner if significant progress is to be made toward the goal of a nuclear-weapons-free world.

To address these problems adequately, the current nuclear disarmament effort must be transformed from a debate among leaders in the NWS to a coordinated global effort of shared responsibilities between NWS and NNWS. This essay outlines a new conceptual framework that is needed to encourage NWS and NNWS to share responsibilities for designing a future nuclear-fuel-cycle regime, rethinking extended deterrence, and addressing nuclear breakout dangers while simultaneously contributing to the eventual elimination of nuclear weapons.

In this introductory essay, we aim first to demonstrate why the question of which states will develop nuclear power in the future matters for global security. To do so, we briefly discuss the connections between nuclear power, nuclear proliferation, and terrorism risks; we present data contrasting existing nuclear-power states with potential new entrants with respect to factors influencing those risks. Second, we introduce major themes addressed by the authors in both volumes, and explain why the expansion of nuclear power, the future of nuclear weapons disarmament, and the future of the NPT and related parts of the nuclear control regime are so intertwined. Finally, we conclude with some observations about what is new and what is not new about current global nuclear challenges. The American Academy of Arts and Sciences has published three important special issues of Dædalus on nuclear weapons issues in the past-in 1960, 1975, and 1991-and reflecting on the differences between the concerns and solutions discussed in those three issues and the nuclear challenges we face today is both inspiring and sobering.