There is something truly baffling about the 2012 presidential candidates hotly debating Planned Parenthood and birth control. These battles were fought — and won — half a century ago. At that time, the vast majority of Americans, nearly all mainstream religious organizations and leaders in both political parties accepted contraception as beneficial to families, society and the world.

The move toward mainstream acceptance of contraception began in the early 20th century and accelerated in the 1940s. In 1942, the Birth Control Federation of America changed its name to the Planned Parenthood Federation of America. Margaret Sanger, leader of the birth control movement, opposed the change. She thought the new name weakened the woman-empowering message of the term “birth control.” But she was overruled. Abraham Stone, medical director of the Margaret Sanger Research Bureau, explained at the time that “planned parenthood” signaled “the need for individual couples to plan their families and for nations to plan their populations.”

As the birth control movement became mainstream, it still took several years for the nation’s leaders to endorse it. In 1959, President Dwight D. Eisenhower declared: “I cannot imagine anything more emphatically a subject that is not a proper political or government activity or function or responsibility. . . . The government will not, so long as I am here, have a positive political doctrine in its program that has to do with the problem of birth control. That’s not our business.”

Just a few years later, President John F. Kennedy — a Democrat and the nation’s first Catholic president — supported family-planning programs as part of foreign aid. Even Eisenhower, JFK’s Republican predecessor, eventually came around, admitting in the mid-1960s: “Once as President, I thought and said that birth control was not the business of our federal government. The facts changed my mind. . . . Governments must act. . . . Failure would limit the expectations of future generations to abject poverty and suffering and bring down upon us history’s condemnation.”

For the next two decades, every American president promoted contraception as an essential part of domestic and foreign policy. Even the Catholic Church considered lifting its prohibition on contraception — and almost did.

Contrary to widely held assumptions, the Catholic ban on birth control is relatively recent and has not been consistently supported by the clergy and the laity. Prior to the 1930s, the church had no official position on contraception. But on Dec. 31, 1930, Pope Pius XI issued a papal encyclical, Casti Connubii (Latin for “Of Chaste Wedlock”), which for the first time explicitly prohibited Catholics from using contraception.

Among those who protested the pope’s decree was Sanger, a daughter of Irish Catholic immigrants. Sanger’s passionate commitment to promoting birth control stemmed from watching her mother weaken and die at age 50, having given birth to 11 children. She blamed her mother’s premature death on constant childbearing and lack of access to contraceptives.

Another opponent of the Catholic ban was John Rock, a devout Catholic doctor who taught at Harvard Medical School and who would become one of the leading clinical researchers responsible for developing the pill. Rock held that contraception was sometimes medically necessary and often personally desirable for maintaining happy marriages and well-planned families. He also believed that birth control was essential for those who could not afford many children. As early as the 1940s, he regularly taught his medical students how to insert diaphragms — even though birth control was illegal in Massachusetts.

Rock was by no means a radical. He was a solid Republican and didn’t approve of sex outside of marriage. But he openly defied the Catholic Church and state laws.

When Rock began research on oral contraceptives, he believed that the pill offered a means of birth control that the church would accept, because it simply repressed ovulation and replicated the body’s hormonal condition in early pregnancy. In 1963, he even wrote a book making the case, called “The Time Has Come: A Catholic Doctor’s Proposals to End the Battle Over Birth Control.”

As momentum built for the church to reconsider its position, Pope John XXIII convened the Second Vatican Council, a gathering of thousands of bishops from all over the world, in 1962. The conference, known as Vatican II, resulted in a number of reforms that modernized church practices. Many believed that afterward, the church’s position on contraception might be relaxed. In fact, Pope John was putting together a committee to consider the matter shortly before he died. It then fell to Pope Paul VI to resolve the issue.

In 1964, Pope Paul appointed a commission on birth control to advise him. As the panel deliberated, anticipation ran high; many journalists, clergy and lay Catholics expected the church to lift the ban. Scottish songwriter Matt McGinn wrote a jaunty tune, recorded by Pete Seeger, about a woman with a house full of children waiting for the pope to “bless the pill.” She buys a package of birth control pills so she will be ready when the church acquiesces. In the final stanza, she hopes to hear the pope’s approval “before my man comes in.”

In 1967, the commission’s report was leaked to the press, revealing that a significant majority of its members favored lifting the ban, including 60 of 64 theologians and nine of the 15 cardinals. The minority who were opposed issued a separate report. After much consideration, the pope issued a formal encyclical, Humanae Vitae (“Of Human Life”) in 1968, siding with the minority and reaffirming the church’s prohibition of any form of artificial birth control.

Catholic leaders quickly criticized the decision. Father Bernard Haring of Rome, widely regarded as the leading moral theologian at the time, called upon Catholic women and men to follow their consciences, rather than the pope’s decree. Countless parish priests agreed and gave sermons to that effect. The pope’s decision had little impact on Catholic women’s use of contraception. Two years after the decree, two-thirds of Catholic women were using contraception. Quickly, the gap between Catholic and non-Catholic women disappeared. According to data from the Department of Health and Human Services, Catholic women use birth control at the same rate as non-Catholic women. The Catholic Church has remained an outlier on the issue, unable to enforce its ban.

By the time the church decided to uphold its prohibition, legal barriers to contraception were crumbling. In 1965,the Supreme Court struck down all state laws that barred access to contraception for married couples; the court extended that right to the unmarried in 1972. Contraception had become a mainstream, pro-family issue.

Bipartisan support for access to contraception began to crumble in the 1980s, during the presidency of Ronald Reagan. In 1984, the United States sent two opponents of abortion rights to a United Nations conference on population in Mexico City. The American delegates established what came to be known as the Mexico City Policy, a global gag rule that refused U.S. government support to any agency, American or foreign, that used its own funds to support abortion services, counseling or referral, even though these services were legal and no federal money was involved. Under the policy, such facilities were prohibited from receiving any U.S. funds for family planning, even if the money would not be used for abortion-related services. The vast majority of Americans opposed Reagan’s gag rule, favoring the inclusion of family-planning information and supplies as part of foreign aid. Nevertheless, the rule prevailed through the Reagan years and the presidency of George H.W. Bush.

The issue became a political football. In 1993, five days after taking office, Democratic President Bill Clinton dropped the Mexico City Policy. Republican George W. Bush reinstated it within days of becoming president. On Jan. 23, 2009, his fourth day in office, Democratic President Obama reversed the policy once again.

Today, according to the Guttmacher Institute, more than 99 percent of sexually experienced women report having used contraception. But we are once again debating whether women should have access to birth control. Fifty years ago, John Rock, the socially conservative, Catholic, Republican doctor, insisted that birth control was consistent with church teachings. He believed that contraception was essential for women’s health and well-being, family happiness, and the good of society. The vast majority of Americans of all faiths and political parties agreed with him at the time. And they still do.

outlook@washpost.com

Elaine Tyler May, Regents professor of American studies at the University of Minnesota, is the author of “America and the Pill: A History of Promise, Peril, and Liberation.”

Read more from Outlook:

Five myths about Planned Parenthood

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