Reason‘s Katherine Mangu-Ward, in her insightful review of Elaine Tyler May’s America + The Pill: A History of Promise, Peril, and Liberation, reminds us that we all have motivations, some obvious, some not. Even knowledge-seeking scientists do. Conventional wisdom now has it that the Pill was pushed by Margaret Sanger, an advocate of eugenics, not just to free women from reproductive slavery, as some would have it, but to keep the wrong kind of women from reproducing. But early researchers and backers of the Pill had other things on the agenda—such as national security. It might get tiring now to hear pundits and pols connect everything, personal and political, to 9/11 and the War on Terror, but May’s book provides evidence that the sexual revolution was really far from the minds of the men who helped launch it.

In public rhetoric, the population bomb was linked closely to the hydrogen bomb. Before Paul Ehrlich’s The Population Bomb, which sold 2 million copies between 1968 and 1974, there was Hugh Moore’s 1954 pamphlet “The Population Bomb.” Moore, who ran the Dixie Cup corporation, thought “voluntary sterilization” could be a weapon in the Cold War. His pamphlet, which was widely distributed by the Hugh Moore Fund for International Peace, declared: “We’re not primarily interested in the sociological or humanitarian aspects of birth control. We are interested in the use…which the Communists make of hungry people.” Overpopulation leads to hunger, Moore argued, and “hunger brings turmoil—and turmoil, as we have learned, creates the atmosphere in which the communists seek to conquer the earth.”

Moore may have been an extremist, but as May notes, even Margaret Sanger, who wasn’t shy about her extreme left-wing views, advocated “national security through birth control.” Not every Cold Warrior cared for contraception; Sen. Joe McCarthy (R-Wis.) worried that the promotion of birth control in America was a plot to spread immorality. But the skeptics were in the minority.

Since healthy, happy people were thought less likely to go red, some alert citizens favored birth control at home to sow good cheer. As early as 1940, a statement from Planned Parenthood declared: “A nation’s strength does not depend upon armaments and manpower alone; it depends upon the contentment…of its people. To the extent that birth control contributes to the health and morale of our people, it makes them less receptive to subversive propaganda, more ready to defend our national system.” The worry then was about Nazis, not communists, but activists had no trouble updating the rhetoric when the Cold War followed World War II. By 1965 this view had percolated up to the mainstream, with President Johnson declaring in his State of the Union address that year, in a section entitled “The Non-Communist World,” that “I will seek new ways to use our knowledge to help deal with the explosion in world population and the growing scarcity of world resources.”

One contraceptive researcher, John Rock, went so far as to say, “The greatest menace to world peace and decent standards of life today is not atomic energy but sexual energy.” It’s not clear whether he was saying that the release of sexual energy was resulting in too many mouths to feed or that a lack of contraception meant that sexual energy wasn’t getting enough release. Either way, it’s an example of how omnipresent the Cold War was in American social life—and, given the far-reaching effects of the Pill over the last 50 years, a good illustration of unintended consequences.