Shortly after the 2016 presidential election was decided, reports on exit polls showed that 81% of white evangelical voters had cast a ballot for Donald J. Trump. On the one hand, perhaps, this outcome was not terribly surprising. White evangelicals have been a heavily Republican constituency at least since 1980, and their support for GOP (Grand Old Party, which is an abbreviation for the Republican Party) presidential nominees had been hovering upward of 75% over the last several contests. Famously invested in the pro-life movement and anxious about the Supreme Court, any normal cycle would find evangelicals on the side of conservatives, and conservative jurisprudence. But, on the other hand, 2016 was not a normal cycle, and Trump was anything but a typical GOP candidate. A real estate mogul turned reality television star with no political experience, he was also a famously unrepentant sinner, with a long and very public history of greed, pride, and lust, among other flaws that should have made him anathema to evangelicals. In the months since November, much of the nation's political-religious discourse has revolved, in some way, around the resulting question: How could America's most self-consciously pious voting block support such a flamboyantly immoral candidate?

Though answers to this question are sure to be both contestable and varied, curious readers will find plenty of context in Frances FitzGerald's The Evangelicals: The Struggle to Shape America, an anticipated, extensive treatment from the prominent journalist and historian. A formidable tome covering nearly 300 years of history, the book traces the lifespan of evangelicalism in the United States from its birth in the 18th century until the Trump inauguration. As she closes the epilogue, the author wonders whether the story of the evangelicals — or, rather, evangelicals of a certain variety — is finally complete.

Though any attempt at summary is sure to be deficient, it is important to note that FitzGerald's work is both careful and comprehensive, and its narrative arch is highly attentive to contextual factors. Though numerous books from history and political science have traversed American evangelical politics, especially in the 20th century, FitzGerald's work has much to offer in its depth and style. Specifically, her analysis remains focused upon evangelicalism as it exists at the nexus of ideas and geography, the point at which the left-right axis intersects with the North-South. One can observe, of course, that evangelicalism is largely based on certain core beliefs and doctrines — about Christ's virgin birth, his sacrificial death, his promise of eternal life for all who believe — and FitzGerald does that with clarity. But the story of evangelicalism in the United States is the story of how these beliefs were adapted to the conditions of economic, political, and social life across a wide expanse of land and the passage of considerable time, and it is here that the book really fulfills its promise.

Beginning with important developments both during and between the Great Awakenings, FitzGerald traces key figures and doctrines as they appeared and prospered — or not — within the new American marketplace of ideas. From very early on, the evangelical narrative was complicated by splits, offshoots, and upstarts, each and all growing in the fertile soil of westward expansion. In time, many of the fractures that had divided believers over particular points of doctrine would coalesce around regional concerns, especially those concerning slavery. As evangelicals in the South circled their wagons against abolitionist criticism, a new condition arose in which citizens who read the same Bible and prayed to the same God could, as Abraham Lincoln would later observe, each invoke His aid against the other. By century's end, the debate over slavery would morph and expand into a definitive disagreement about the nature and purpose of evangelical life, with many embracing a reformist faith pursuant to social justice on earth, and others focused specifically on transporting souls to heaven.

This division would lay the groundwork for evangelical struggle in the 20th century, as liberal — or modernist — proponents of the Social Gospel squared off against conservative fundamentalists. Though fundamentalism was born in the intellectual centers of the North, it found its most receptive audience in the congregations of the South, lending itself to a relatively isolated and famously nostalgic society. Here, as elsewhere in the text, FitzGerald's attention to regional influences proves vital to understanding the dynamics of longitudinal change. By 1925, when William Jennings Bryan was railing against Darwinism in Dayton, Tennessee, it seemed that the fundamentalists were on the ascent. But subsequent events — including a Great Depression and another World War — would preoccupy the nation and direct its religious energies toward other matters. Many historians have reported on the decline of fundamentalism in the decades after the Scopes trial, but these likely overstate the case. Though perhaps in remission, fundamentalist fervor would return in the 1960s, this time in a more concerted political form.

Relatively small as a proportion of the nation's entire history, the 57 years from 1960 to the present account for about two-thirds of FitzGerald's book, situating the history of the new Christian Right atop the history of the forms that came before. The major figures of the 20th century feature prominently in the text, along with the organizations that they founded and fostered — usually out of the South. Billy Graham, Jerry Falwell, Pat Robertson, and a whole cast of televangelists, many controversial, each has their moment here, and each gets analyzed. Also featured are movement intellectuals Francis Schaeffer and Rousas John Rushdoony, whose influence is explained with clarity and generosity. These sections provide the context for a marathon, 100-page chapter on George W. Bush, the evangelical man-of-the-hour who, Fitzgerald argues, marked the culmination of evangelical influence in the United States.

This brings us back, by turns, to the present and the President. FitzGerald closes the book with some thoughts on the state of evangelicalism here and now, suggesting that the polls touting uniform evangelical support for Trump only obscure deep, subterranean fissures. Citing the rise, in recent years, of vocal progressives within evangelical organizations, as well as demographic shifts in the direction of a younger, more diverse population, FitzGerald argues that the evangelicals of the future are unlikely to rebuild the political consensus they had enjoyed in previous decades. Though evangelicalism will undoubtedly continue on as a religious faith, it will probably weaken as an explicitly conservative political force. This reader, for one, hopes that she is right.