After the September 11, 2001 terrorist attacks on the World Trade Center and the Pentagon, many scholars, journalists, and public officials expressed fear about the security of nuclear facilities in the United States.

The reaction to this new terrorist threat has been strong and predictable. Emergency efforts began immediately to deploy more security forces to protect U.S. nuclear facilities after the September 11 attacks. Experts testifying to Congress have strongly advocated adding more security guards and patrols at nuclear facilities to prevent nuclear terrorism. The increased threat of nuclear terrorism, it is argued, must be met with a countervailing increase in nuclear security personnel.

There are understandable incentives for organizational leaders to want to devote more resources and more personnel to address dangerous problems when they are seen to develop. From a political perspective, action must be taken after a major disaster, at a minimum, to let insiders and outsiders see that top officials are doing something to prevent a reoccurrence. If the causes of the problem are uncertain, however, the appropriate reaction is unclear. This article analyzes how we should think about nuclear security and the emerging terrorist threats. It presents a warning about the most simple, and most tempting, solution to our new nuclear terrorism problem: to add more security forces to protect power plants, weapons facilities, and nuclear storage sites. The article uncovers the dark side of redundancy by focusing on how efforts to improve nuclear security can inadvertently backfire, increasing the risks they are designed to reduce.

Opponents rarely go to war without thinking they can win--and clearly, one side must be wrong. This conundrum lies at the heart of the so-called "war puzzle": rational states should agree on their differences in power and thus not fight. But as Dominic Johnson argues in Overconfidence and War, states are no more rational than people, who are susceptible to exaggerated ideas of their own virtue, of their ability to control events, and of the future. By looking at this bias--called "positive illusions"--as it figures in evolutionary biology, psychology, and the politics of international conflict, this book offers compelling insights into why states wage war.

Johnson traces the effects of positive illusions on four turning points in twentieth-century history: two that erupted into war (World War I and Vietnam); and two that did not (the Munich crisis and the Cuban missile crisis). Examining the two wars, he shows how positive illusions have filtered into politics, causing leaders to overestimate themselves and underestimate their adversaries--and to resort to violence to settle a conflict against unreasonable odds. In the Munich and Cuban missile crises, he shows how lessening positive illusions may allow leaders to pursue peaceful solutions.

The human tendency toward overconfidence may have been favored by natural selection throughout our evolutionary history because of the advantages it conferred--heightening combat performance or improving one's ability to bluff an opponent. And yet, as this book suggests--and as the recent conflict in Iraq bears out--in the modern world the consequences of this evolutionary legacy are potentially deadly.

Should ethnonationalist wars be resolved by formally partitioning states? The answer can't be decided case by case, because two incentive problems imply that ad hoc partitions have effects that extend across cases.

First, if the implicit criterion for major power intervention in support of partition is some level of violence, this encourages violent movements seeking to mobilize cultural difference in order to claim statehood. The Wilsonian diagnosis is wrong. Perpetual civil peace cannot be had by properly sorting "true" nations into states, because nations are not born but made, partially in response to international incentives and major power policies.

Second, an international order in which major powers go around carving up lesser powers on an ad hoc basis would make all states significantly less secure. Ad hoc use of partition to solve civil wars would undermine a relatively stable implicit bargain among
the major powers in place since the 1950s - "If you don't seek to change interstate borders by force, neither will we." I argue that this norm has been valuable, functioning in some respects like an arms control agreement. It would be irresponsible to undermine it without a thought to what might replace it, as the advocates of ad hoc partition are effectively urging. If the major powers want to start redesigning "sovereign" states, they need a political and legal framework that mitigates these two incentive effects. The best feasible solutions may be:

(1) strengthening and making more precise international legal standards on human
(and perhaps group) rights;

(2) threatening to sanction states that do not observe these standards in regard to minorities, possibly including some forms of support for agents of the
oppressed group;

(3) holding to the norm of partition only by mutual consent, but providing carrots and sticks when the state in question refuses to abide by minimal standards of
nondiscrimination.

As the American military extends its stay in postwar Iraq, the risks of political and social friction will rise. Inevitably, there will be clashes; protests erupted in May, for example, when soldiers searching for troublemakers in one town intruded on unveiled women. To keep the occupation of Iraq from ending in bitterness, American officials will have to reach out to residents both economically and politically.

To that end, they might want to consider the long-term occupation of another place where Americans haven't been universally welcomed: Okinawa. This island witnessed the bloodiest battle of World War II, losing a third of its population. The American military administered the island until 1972, when it reverted to Japanese rule. Today, 24,000 American troops are stationed there, and the military occupies one-fifth of the land.

There is a tradition of antimilitarism on the island, fed in part by the horrors of the Battle of Okinawa, and there is an active movement to evict the American troops. Yet most islanders get along well with the service members, and anti-American violence is rare. Three important lessons can be drawn from Okinawa for the American presence in postwar Iraq.

First and most obvious, commanders must do everything possible to stop criminal or just plain disorderly conduct by American personnel. Military officials on Okinawa realized the importance of this when protests arose in 1995 after three servicemen raped a 12-year-old Okinawan girl. The officials responded by establishing intensive educational campaigns that instilled the importance of good community relations in service members and their families. Personnel are now checked for drunkenness as they enter and leave the bases, and unarmed patrols in areas where G.I.'s socialize discourage bad behavior.

These measures appear to be helping: the military says American personnel and their families commit 1 percent of the crimes on the island, even though they are 4 percent of the population. And while protests against the bases continue, tensions have eased considerably since 1995.

While it's vital to discourage crime, it's also important to be seen as an actively beneficial presence. The second lesson of Okinawa is that the United States should try to contribute to the local economy, and to spread its largess.

American bases in Okinawa provide thousands of jobs to locals. The Americans are consumers too, keeping small businesses afloat. The islanders who lease the land for the bases collect above-market rents, and local governments get public works money from Tokyo as a side payment for bearing the "basing burden." That means a critical mass of Okinawans is reluctant to see the American bases disappear. To build goodwill in Iraq, officials should ensure that many different local interests profit from the American presence.

The third lesson is that American officials should establish strong lines of communication with the local authorities, not just with national officials - especially if, as on Okinawa, they represent a distinct ethnic group. To give islanders more of a voice, there is a tripartite committee for Okinawan, American and Japanese officials to discuss base-related matters. In Iraq, community representatives must likewise be included in base negotiations, especially in the Kurdish north and Shiite south.

As part of these efforts, a vigorous volunteer program like the one on Okinawa - involving everything from teaching in local schools to assisting the disabled - can help convince residents that American troops are on their side. Rebuilding security will be the greatest long-term challenge in postwar Iraq. Learning from the United States experience on Okinawa can help ensure the success of the Iraqi occupation, enabling the troops to come home all the more quickly.

Imagine a scenario in which terrorists begin attacking urban centers. The government responds with widespread detention; extended powers of arrest, search and seizure; increased surveillance capabilities; and the creation of a special court to try terrorist suspects. Before long it is sanctioning inhumane treatment of prisoners and the use of military force.

That is how the British government responded in the early 1970s to the start of Northern Ireland's Troubles. The effect was devastating. The new measures alienated the minority Catholic population and breathed life into a near-defunct Republican movement. More than 3,600 people died in the decades of violence that ensued. The provisions also carried heavy economic and political costs, both at home and abroad. Most critically, they undermined the state's political legitimacy at a time when an avowedly violent movement sought to destabilize the government.

The erosion of individual rights carries significant domestic and foreign-relations consequences. Beyond this, a more fundamental question arises: Has America remained true to its founding principles?

An influential conventional wisdom holds that civil wars proliferated rapidly with the end of the Cold War and that the root cause of many or most of these has been ethnic and religious antagonisms. We show that the current prevalence of internal war is mainly the result of a steady accumulation of protracted conflicts since the 1950s and 1960s rather than a sudden change associated with a new, post-Cold War international system. We also find that after controlling for per capita income, more ethnically or religiously diverse countries have been no more likely to experience significant civil violence in this period. We argue for understanding civil war in this period in terms of insurgency or rural guerrilla warfare, a particular form of military practice that can be harnessed to diverse political agendas. The factors that explain which countries have been at risk for civil war are not their ethnic or religious characteristics but rather the conditions that favor insurgency. These include poverty--which marks financially & bureaucratically weak states and also favors rebel recruitment--political instability, rough terrain, and large populations.