Nearly 40 years after the concept of finite deterrence was popularized by the Johnson administration, nuclear Mutual Assured Destruction (MAD) thinking appears to be in decline. The United States has rejected the notion that threatening population centers with nuclear attacks is a legitimate way to assure deterrence. Most recently, it withdrew from the Anti-Ballistic Missile Treaty, an agreement based on MAD. American opposition to MAD also is reflected in the Bush administration's desire to develop smaller, more accurate nuclear weapons that would reduce the number of innocent civilians killed in a nuclear strike. Still, MAD is influential in a number of ways. First, other countries, like China, have not abandoned the idea that holding their adversaries' cities at risk is necessary to assure their own strategic security. Nor have U.S. and allied security officials and experts fully abandoned the idea. At a minimum, acquiring nuclear weapons is still viewed as being sensible to face off a hostile neighbor that might strike one's own cities. Thus, our diplomats have been warning China that Japan would be under tremendous pressure to go nuclear if North Korea persisted in acquiring a few crude weapons of its own. Similarly, Israeli officials have long argued, without criticism, that they would not be second in acquiring nuclear weapons in the Middle East. Indeed, given that Israel is surrounded by enemies that would not hesitate to destroy its population if they could, Washington finds Israel's retention of a significant nuclear capability totally "understandable." Then, there is the case of India and Pakistan, two countries allied with the United States in its war against terror. Regarding these countries' nuclear arsenals, U.S. experts argue, is to help these nations secure their nuclear capabilities against theft. To help "stabilize" the delicate nuclear balance between India and Pakistan, they argue, it might be useful for the United States to help enhance each country's nuclear command and control systems. Yet, U.S. officials have opposed these two nations' efforts to perfect their arsenals for battlefield applications and nuclear war-fighting use. Instead, U.S. officials have urged both India and Pakistan to keep their forces to the lowest possible levels and develop them only for deterrent purposes. This is understood to mean only targeting each others' major cities. Implicit to all this talk is the assumption that a nation's security is, in fact, enhanced by acquiring a relatively modest but secure nuclear arsenal (i.e., one most likely to be used only to strike large, soft targets, such as cities). Certainly, the underlying premise of MAD thinking, that small nuclear states can deter aggression by large nuclear states, is still popular. Iraq, we are told, might have held America off in 1991 or 2001 had it actually possessed nuclear arms. Similarly, the contrast between U.S. and allied generosity toward North Korea and the harsh treatment doled out to Saddam is usually explained by referring to the likelihood of North Korea having nuclear weapons and of Iraq clearly not. Why should we care about such MAD-inspired notions? They make U.S. and allied efforts to prevent the spread of nuclear weapons much more difficult. If, as MAD thinking contends, nations can deter aggression by having the ability to successfully launch a nuclear attack against a significant number of innocent civilians, acquiring a nuclear arsenal will increasingly be seen as the best way for states to protect themselves.