Ten years ago, the last Harvard graduating class of the 20th century faced what seemed to be an optimistic future, premised on what was then a prosperous and conflict-free world order. Not only was the Cold War long past, but also the European Union was flourishing as the emblem of post-nationalist global cooperation, and the North Atlantic Treaty Organization had launched an international coalition to bring order to the Balkans. To be sure, Americans and other innocent people had lost lives to terrorism, but it was far from America’s shores. At home, the Internet was fueling explosive stock growth, and steady increases in home prices and the Dow Jones Industrial Average created confidence that predictable prosperity lay on the horizon.

This year’s graduating class looks at a different prospect. The illusion of a peaceful post-Cold War world has been shattered. While Iraq is perhaps headed to a relatively stable and democratic future, we currently must continue to shoulder the majority of the burden of the conflict in Afghanistan as NATO’s contribution dwindles. Radical Islamist terrorism has cost thousands of American lives and is gestating in ungoverned territories in South Asia, Yemen, Somalia, and North Africa. A bellicose Iran is approaching the nuclear threshold. Pirates range across the Indian Ocean. Across our own southern border, the Mexican government is struggling with sophisticated organized crime cartels over the control of significant portions of northern Mexico—a struggle that could spill into the United States.

This breakdown in global security has been accompanied by an even more dramatic reversal of global economic fortunes. In early 2000, the dot-com bubble burst. More significantly, the rise in asset values that supported much global prosperity turned out to be an illusion largely fueled by easy credit; when the bubble burst, highly leveraged speculative positions reversed gear, and the international financial system came uncomfortably close to crashing. Even more troubling, the ongoing Greek debt crisis has suggested that weaknesses in sovereign debt may trigger another, even more profound global financial meltdown.

Looking back, the past decade appears as a succession of collisions between the optimism of 2000 and brutal reality. If there is a consistent theme to the past 10 years, it is that we have consistently underestimated the likelihood and impact of negative, high-consequence events. The assumption that a past run of peace and prosperity is assured for the future has led us to confuse wishful thinking with disciplined planning and preparation.

For graduates of 2010, the future will require a new, more tough-minded way of thinking for every professional discipline.

International relations: Global security can no longer be preserved through focus on nation-states alone. The spectrum of transnational threats, from terrorists to international drug cartels, must be an additional subject of national-security focus. The traditional tools of war fighting and statecraft must be blended with the skills of development, policing, cultural studies, and institution building.

Business and economics: The free market is still the foundation of prosperity, but the rules of the road have to change to align benefits and costs with decision-making. We have felt the consequences of bankers leveraging other people’s money on speculative bets or politicians dispensing favors using debt that will be saddled on the next generation. The new architecture of business and political economy will have to assure that those who gamble must bear their own losses, and that public spending does not distribute benefits today while postponing burdens until the next generation.

Law: Modern technology and the Internet have delivered enormous capability into the hands of institutions and individuals around the globe. However, our dependence on this network carries the seeds of great vulnerability. Protecting our assets and the security of our transactions in cyberspace is not only a technical challenge, but also a legal challenge. What are the legal responsibilities of institutions and even countries for securing global cyberspace against "rogue" threats arising within their own domains? What are the rules and laws of cyber warfare? What is the new legal construct for privacy in an age when so much of our lives are lived through the Internet, and the capacity to store and disseminate this data is almost without limit? The technology to address these issues can only be intelligently developed if we have a legal superstructure within which it will be operated.

Public health: Globalization is a public-health hazard. While the recent H1N1 pandemic was non-lethal, there is a disturbing likelihood that either a natural, fatal pandemic will occur or a biological weapon will be unleashed in the near future; global travel and trade patterns make it virtually impossible to cabin such outbreaks. Our public-health models and institutions are not geared to prepare for such a catastrophic health emergency—and yet, such an emergency is becoming more likely. Part of the answer will be research and technology, but much of the outcome will depend upon planning and preparation, which must engage not only the medical and public-health communities but also the whole gamut of public and private institutions.

In the end, the class of 2010 does not face a more threatening world than did the class of 2000; the threats are simply more apparent. But with all of this comes an unusual opportunity for this graduating class to shape the globe at a point of inflection.

Michael Chertoff ’75 is the former United States Secretary of Homeland Security.