While conservative Christians have led historic crusades against a number of "evils" in America — witchcraft, alcohol, communism, feminism and abortion, among others — homosexuality was never more than a minor concern until 1969, when protests in New York City launched the contemporary gay rights movement. The first stirrings of anti-gay organizing came the following year when, according to historian Susan Fort Wiltshire, ambitious small-town preachers in the Northwest Texas Annual Conference of the United Methodist Church began to exploit anti-gay sentiment. These preachers realized that virulent anti-gay rhetoric could "fill football stadiums for revivals in such tiny Panhandle towns as Tulia and Clarendon and Higgins and Perryton," Wiltshire says.

The crusade went national in 1977, courtesy of Anita Bryant. Best known as a spokeswoman for Florida orange juice, Bryant had converted a runner-up finish in the 1959 Miss America pageant into a lucrative career singing "wholesome family music." Bryant later said she knew next to nothing about gay people when she attended a 1977 revival at Miami's Northside Baptist Church. The preacher there railed against a new Dade County ordinance that protected gay people from discrimination, saying he would "burn down [his] church before [he] would let homosexuals teach in its school." Bryant was so impressed by the dangers of this new "homosexual agenda" that she launched an initiative to overturn the anti-discrimination ordinance, winning with a 70% vote.

Bryant then founded a national group called Save Our Children. She took her anti-gay message on the road, helping fundamentalists organize anti-gay ballot campaigns in the handful of American cities that had passed gay rights laws. These ballot initiatives would become the single most important organizing tool for the fundamentalist right, transforming thousands of previously apolitical churchgoers into grassroots activists. Like many modern anti-gay groups, Save Our Children's primary tactic was fear-mongering. Not only were gay men and lesbians "sick," "perverted" and "twisted," they posed a very real threat to American families.

Save Our Children collapsed in 1979, after Bryant had a well-publicized divorce and breakdown, but not before her success in getting national publicity and large donations caught the eye of right-wing strategists like Paul Weyrich and Richard Viguerie, the pioneer of right-wing direct-mail fundraising. The campaign was also picked up by more explicitly religious leaders. Inspired by Bryant, budding Christian Right "family activist" Tim LaHaye painted a full-blown portrait of alleged gay desperation in his 1978 book, The Unhappy Gays. LaHaye, now famous for co-authoring the blockbuster Left Behind series of end-of-the-world religious thrillers, wrote that succumbing to the demands of the gay rights movement would be a mistake of apocalyptic proportions — literally. "The mercy and grace of God seem to reach their breaking point when homosexuality becomes normal," LaHaye wrote. "Put another way, when sodomy fills the national cup of man's abominations to overflowing, God earmarks that nation for destruction."

The cover of The Unhappy Gays featured a close-up photograph of rusty chains, symbolizing the "captivity" of homosexuality, a popular theme in anti-gay circles. "Moral fidelity among homosexuals is almost unknown," LaHaye claimed, citing as evidence "one psychologist writer" (unnamed) who "suggests that it is not uncommon for a homosexual to ‘have sex' with as many as 2,000 different people in a lifetime." This "incredible promiscuity" leads to a life of lonely, selfish desperation, he wrote, but there is hope: "Homosexuals are made, not born!" and can be cured by being "born again."

This idea that being gay is a choice is a key concept in the anti-gay movement. If homosexuality is genetic, as most scientists believe, the movement to deny equality to LGBT people is just as discriminatory as Jim Crow segregation, an analogy anti-gay groups want to discourage. For that reason, several Christian Right groups, in particular Focus on the Family, offer a religious type of "therapy," often called reparative therapy, that supposedly "cures" homosexuality. Today, there are at least 200 such "ex-gay" programs run by American churches, religious counseling centers and religious colleges.

These reparative or ex-gay therapies have been discredited by virtually all major American medical, psychiatric, psychological and professional counseling organizations. The American Psychological Association, for instance, declared in 2006: "There is simply no sufficiently scientifically sound evidence that sexual orientation can be changed. Our further concern is that the positions espoused by NARTH [the National Association for Research & Therapy of Homosexuality] and Focus on the Family create an environment in which prejudice and discrimination can flourish." The American Medical Association, for its part, officially "opposes the use of ‘reparative' or ‘conversion' therapy that is based on the assumption that homosexuality per se is a mental disorder or based upon the a priori assumption that the patient should change his/her homosexual orientation." These organizations and other professional associations uniformly reject the idea that homosexuality is a mental illness.

Defamatory propaganda about gays and lesbians is a mainstay of the anti-gay movement. Perhaps the most influential anti-gay propagandist is Paul Cameron. After losing his job teaching psychology at the University of Nebraska, Cameron set himself up as an independent sex researcher in the late 1970s, churning out scores of anti-gay pamphlets that were distributed mostly in fundamentalist churches. Cameron's "studies" falsely concluded that gay people were disproportionately responsible for child molestation, serial killings and the spread of sexually transmitted diseases. Gay people, according to Cameron's baseless claims, were obsessed with consuming human excrement, allowing them to spread deadly diseases simply by shaking hands with unsuspecting strangers or using public restrooms.

Cameron's research was debunked repeatedly in newspaper and magazine exposés, which showed his studies to be anything but scientific. But he soldiered on. Even after being expelled from the American Psychological Association in 1983 for violating ethical standards in his work, Cameron tried to stay in the game by now referring to himself as a sociologist — until the American Sociological Association passed a 1986 resolution declaring, "Paul Cameron is not a sociologist, and [this group] condemns his constant misrepresentation of sociological research."

Despite the crackpot nature of Cameron's theories and methodology and its very public debunking, his claims were extolled by numerous leading figures of the religious right. Right-wing commentator Pat Buchanan and William Bennett, secretary of education in the Reagan administration, were publicly embarrassed when they touted Cameron's 1993 study claiming that gay men have only a 42-year life expectancy. As reporters quickly discovered, Cameron had based the study on obituaries printed in a few gay newspapers — hardly a scientific sample.

In recent years, the Christian Right has been incensed by court decisions favoring gay equality. Particularly enraging to its leaders was the 2003 U.S. Supreme Court ruling that overturned the convictions of two Texas men arrested for having consensual sex. Writing for the majority in Lawrence v. Texas, Justice Anthony Kennedy said the men were "entitled to respect for their private lives." The state, he declared, "cannot demean their existence or control their destiny by making their private sexual conduct a crime." The decision was remarkably popular. A national survey found that 75% of Republicans and 88% of Democrats wanted to see state sodomy laws struck down, as they were by the Lawrence decision.

For religious crusaders, however, Lawrence was the most unsettling court decision since Roe v. Wade, which legalized abortion. Fundamentalist groups filed 15 briefs supporting Texas' sodomy laws, only to see their arguments — that gay sex was a threat to public health and "traditional family values," and that gay people do not deserve equal rights — shot down. "Six lawyers robed in black have magically discovered a right of privacy that includes sexual perversion," said an infuriated Jan LaRue, chief counsel for Concerned Women for America, a hard-line Christian Right group. "This opens the door to bigamy, adult incest, polygamy and prostitution," added Ken Connor, president of the Family Research Council.

Even more troubling in these quarters was the 2004 decision of the Massachusetts Supreme Court holding that gay citizens had a right to marry under that state's constitution. In the wake of that decision, anti-gay leaders ratcheted up their call to arms. "America stands at a defining moment," said Lou Sheldon, founder of the Traditional Values Coalition, which has touted Cameron's claims for years. "The only comparison is our battle for independence."

Immediately after the Lawrence decision, the now-deceased D. James Kennedy, president of Coral Ridge Ministries, issued a similar call to arms. Now that America's courts were "officially off-limits to the moral framework that has allowed us to enjoy freedom and prosperity," Kennedy said, the holy war on gay rights should be renewed on the battlefront of public opinion. Kennedy and other anti-gay activists began pressing for a federal law banning gay marriage. For right-wing evangelical ministries like his Coral Ridge Ministries, which brings in more than $35 million annually, the stakes were never higher.

Since Lawrence, dozens of states have passed referenda, laws and amendments banning gay marriage, and groups like Coral Ridge and Focus on the Family have spent millions on ad campaigns and get-out-the-vote campaigns to support those efforts. Marriage equality remains a hot topic on cable TV and talk radio, especially on conservative shows. At the same time, however, a growing number of states have legalized gay marriage, and public acceptance of such unions has been growing. Ultimately, some legal and political experts believe, marriage and other types of equality for gays is likely to become the law of the land.