The Christian “purity” movement promoted a strict view of abstinence before marriage. But two decades later, some followers are grappling with unforeseen aftershocks.

To the uninitiated, Christianity’s evangelical movement can seem like a monolith that brooks no dissent on certain core issues: Same-sex relationships are sinful, men’s spiritual dominance over women is divinely ordained and, on the political front, Donald J. Trump was an improbable but nonetheless valued protector of the faith.

Not everything is what it appears to be. The movement is in fact rife with division, a reality reinforced last month when Beth Moore, an evangelical writer and teacher with a huge following, formally ended her long affiliation with the Southern Baptist Convention, principally because of its tight embrace of the licentious, truth-challenged Mr. Trump.

It was a rupture several years in the making. As Ms. Moore told Religion News Service, disenchantment took hold when Mr. Trump became “the banner, the poster child for the great white hope of evangelicalism, the salvation of the church in America.” But the former president’s behavior is not the only issue buffeting the evangelical movement. White supremacy, male subjugation of women, a spate of sexual abuse cases, scandals involving prominent figures like Jerry Falwell Jr. — all have combined to undermine the authority of religious leaders and prompt members like Ms. Moore to abandon the Southern Baptist Convention.

Retro Report, which examines through video how the past shapes the present, turns attention to an artifact of religious conservatism from the movement. This is the so-called purity pledge, taken in the main by teenagers who pledged to abstain from sex until they married. Some swore to not so much as kiss another person or even go on a date, for fear of putting themselves on the road to moral failure.