1940s: War production during World War II brings women out of the home and into the factories. War production also brings the U.S. economy out of the Great Depression.

1960s: The Vietnam War brings students out of the classroom to protest the draft, the war, and the deaths of thousands of their peers.

1990s: The Gulf War causes very little reaction in the United States.

1940s: The great weapon of mass destruction during World War II is the atomic bomb. Thousands of people are killed in Hiroshima and Nagasaki, and even more suffer from the effects of radiation.

1960s: Agent Orange is used in Vietnam to defoliate the tropical jungles. Soldiers who are inadvertently sprayed with Agent Orange suffer from many physical ailments including sterility and possibly cancer.

1990s: Biological warfare is feared during the Gulf War, and so the U.S. troops...