This is from W. Scott Poole’s 2009 book Satan in America: The Devil We Know:
Left Behind also sought to make an evangelical case for some of the contemporary cultural and political struggles of the 1990s. Its emergence as a publishing phenomenon coincided with a public movement for gay, lesbian, bisexual and transgender rights. … Conservatives, many of them affiliated with the Christian Right, warned darkly of the “homosexual agenda” and began the so-called pro-marriage movement that would eventually result in calls for constitutional amendments at the state and federal level that sought to “preserve traditional understandings of marriage.”
[Tim] LaHaye had long been an opponent of civil rights for gay and lesbian Americans and was associated with some of the most extreme elements in the antigay movement. His 1980 book What Everyone Should Know About Homosexuality combined scriptural references to homosexuality with the writings of Paul Cameron, a researcher expelled from the American Psychological Association for a variety of absurd claims, including that homosexuals were responsible for half of all sex-related murders and that Thomas Jefferson had favored castration for gay men and facial mutilation for lesbian women.
LaHaye definitely links homosexuality with the devil in Left Behind. In the series homosexuality becomes the literal conduit through which Satan enters the world of the last days. In a prequel novel entitled The Rising, the birth of the Antichrist is described as being brought about by a conspiracy of “international bankers” who accept sperm donations from two gay men. The Antichrist has two daddies, claims LaHaye, a point the authors seems to use to represent a kind of satanic inversion of the Christian doctrine of the virgin birth. … The Christian horror genre created by LaHaye drew on fears about changing cultural mores and the slow but steady gains for human rights in American politics. Satan, once again, was constructed as the ultimate origin of any effort toward progressive political change.… Left Behind seeks to inspire readers to become fully engaged in contemporary struggles, indeed to become soldiers in the culture war. Given this charge, violence becomes redemptive rather than an aspect of evil. The books feature a symmetrical amorality in which both the forces of the Antichrist and the “Trib Force” (evangelical believers who are “saved” after the Rapture) make use of deadly violence in their struggle against one another. In fact, “Trib Force” resembles nothing so much as a Christian fundamentalist al-Qaida, a secret, underground network willing to make use of cyber-terrorism, assassination, and targeted bombing to challenge a satanic modernity. As one member of the group says, “Woe to those who believe God is only love. We are engaged in a worldwide battle with Satan himself for the souls of men and women.” Jesus Christ himself gives his blessing to these ideas when he returns in Glorious Appearing, book number 12 in the series. His “Second Coming” marks the death of tens of thousands, “their blood pooling and rising in the unforgiving brightness of the glory of Christ.”
The Left Behind series allowed the image of Satan in American culture to grow freely, and often exotically, from the soil of the American culture wars of the 1980s, which only gained strength in the last decade of the century. Often initiated by the Christian Right, the culture clashes brought a vigorous response from critics on both the secular and religious left, and for many evangelicals, they represented the struggles against the forces of darkness at the twilight of the world depicted in the fictional narratives of Tim LaHaye and Frank Peretti.
The anger generated by the American culture wars owed much to the idea that disagreement over social and cultural issues had, at back of them, a struggle with evil. Tim LaHaye has said that a “religious war” is being waged in America. “We,” he explained to one evangelical audience, “need to aggressively oppose secular humanism; these people are as religiously motivated as we are and they are filled with the Devil.” In LaHaye’s understanding, there are only two stark options in America’s ideological divide. The secular left, inspired by Satan himself, and the Christian Right, which seeks to overturn Roe v. Wade, stop the expansion of gay and lesbian rights, introduce prayer into public schools, and remove the teaching of evolutionary science.