On June 22–23, 2001, a group of former senior U.S. government leaders met at Andrews Air Force Base to participate in the “Dark Winter” crisis exercise sponsored by four nongovernmental organizations. Against a backdrop of rising tensions in East Asia and Southwest Asia, exercise participants were confronted with a terrorist attack of smallpox in three American states. As the exercise progressed over twelve days, the players watched helplessly as a smallpox epidemic spread to 16,000 people in 25 states and to 15 other countries. The spread of this contagious virus was accompanied by other domestic and international consequences for the United States, including increased crime, civil unrest, plummeting confidence in the institutions of government, the disintegration of alliances, and problems projecting power overseas.
Less than three months later, the United States suffered the largest terrorist attack in its history when terrorists struck the World Trade Center and the Pentagon on September 11. Only three weeks after that, a letter containing anthrax arrived at the headquarters of the American Media Inc. in Florida; this was soon followed by similar letters to media companies and American political leaders. The daily reports of new anthrax cases, both real and suspected, overshadowed the U.S. military attacks on Afghanistan and made the American public more fearful than it had been at any time since the Cuban Missile Crisis. Biological weapons terrorism, a subject that had largely been confined to narrow policy circles, was now receiving constant media coverage. The biological terrorism of the Dark Winter exercise had become a real specter for America.