America's Protestant mainline has vacillated from a position of social and cultural prestige to being one facet of American Christianity that has experienced steep decline. Once the vanguard of the nation's religious heritage, it has fallen from popularity during the past century. Since the 1950s, sociologists have grappled with the vexing question of why the Seven Sisters—the United Church of Christ, the Episcopal Church, the Evangelical Lutheran Church in America, the United Methodist Church, the Disciples of Christ, the American Baptist Convention, and the Presbyterian Church (USA)—have experienced decreasing and aging memberships while also exerting less influence in American public life. The conventional thesis is that the liberalizing turn in mainline theology has not appealed to the public as denominational leaders hoped. Instead, theologically conservative, evangelically oriented churches have swelled in the second half of the twentieth century. Jason Lantzer offers a new interpretation of this decline, one that looks at multiple social, political, economic, and ecclesiastic conditions. His analysis is a refreshing revision that also introduces the new American mainline.

At the outset, Lantzer explains to the reader that the term “mainline” has a fluctuating definition. Historically, people have applied this term to the numerically largest Protestant denominations, the Seven Sisters. Lantzer finds this characterization problematic because of the numerical losses that plague each denomination. Instead, he defines the mainline as the “most culturally influential and demographically representative group of denominations at a given historical moment” (3). This statement is without a doubt Lantzer's crowning achievement because it reorients our use of the term. The mainline's influence and representation was critical to its role in shaping a Protestant consensus, he claims.The historical context is vital to understanding who constitutes the mainline. The mainline becomes not an exact set of denominations, but rather a changing lineup of religious groups that serve as the unofficial religious establishment in the United States. Lantzer's book serves as a narrative of that lineup change and why the change occurred.

The book employs both history and sociology. Readers will be able to identify these disciplines as there is a sharp contrast between the historical and sociological chapters. Chapters 1 and 2 narrate the rise of the Protestant mainline from its colonial beginnings to its ruptures in the modernist-fundamentalist controversy of the 1920s. These chapters are historical in nature and present a clear narrative of American religion. At times the narrative is over simplified. Chapter 3 is a transitional chapter that narrates the decline of the Episcopal Church in the 1960s and 1970s while also analyzing the structures within the denomination that contributed to a fissure between modernists and traditionalists. Chapters 4 through 7 are more sociological in nature, as evident in their thematic arrangement. Chapter 4 analyzes the political spectrum inhabited by theological conservatives and liberals. Chapter 5 outlines the three structures of consumerism, communications revolution, and cultural engagement that explain why churchgoers are opting for conservative congregations. Employing both supply-side and demand-side perspectives, Lantzer shows how these three facets constitute the paradigmatic shift that challenges older interpretations of mainline decline. Chapter 6 takes a global perspective on the mainline. While the mainline is declining in the United States, its missions abroad or members of its global fellowship are thriving. Conservative, evangelical Christianity—even among mainline denominations—is excelling, especially in the Global South. These phenomena point to the fact that liberal, mainline Protestantism wanes in the global context. That conservative, evangelical Christianity is robust around the world is also putting pressure on the liberal contingents in America's mainline denominations to enact change and conform to the historical and global consensus. Finally, in chapter 7 Lantzer introduces a new mainline. It has three lines: evangelical, Roman Catholic, and Pentecostal.

The book is a welcome addition to the discussion of mainline Protestantism in the United States, but it is not without its limitations. First, while Lantzer frequently mentions the Seven Sisters, he does not focus much on the history of these denominations. Instead, he analyzes parachurch organizations more often. When Lantzer does focus on denominations, he usually discusses either the Episcopal Church or the United Methodist Church. The other sisters get only scant mention. Second, he oversimplifies the formation of the Protestant mainline in American history. Lantzer assumes that Protestantism in America formed a consensus in the eighteenth and nineteenth centuries that made for the unofficial establishment. He then narrates a downfall in the twentieth century. Lantzer focuses too much on the seeds of denominational discord in the 1920s and 1960s and brushes over the controversies in the First and Second Great Awakening. He acknowledges that New Lights and Old Lights were at odds in the eighteenth century, but celebrates that both groups were instrumental in stemming Deism (22). His discussion of the Second Great Awakening extols the contributions of the Beecher family as evangelicals par excellence without any consideration of their marked differences from and opposition to Charles Finney's New Measures. The nineteenth-century mainline appears to be a little too evangelical and too monolithic, and parsing out the mainline's divergences in the eighteenth and nineteenth centuries would help to explain why the fissures deepened in the twentieth century. Third, while his definition of a new mainline is welcome, it may not fit his consensus model of the mainline. Lantzer argues that the historic mainline achieved consensus, and that was one of its hallmarks. The new mainline is much more diverse racially, ethnically, politically, and economically. It is also both Protestant and Roman Catholic. It is certainly in keeping with the trajectory of American pluralism. But it is still very much a Christian mainline. Also, it may not succeed in meeting all of Lantzer's own criteria. The new mainline may be more demographically representative and culturally influential, but it does not maintain a consensus. This new mainline likely will not maintain consensus, given the range of diversity within it and the fact that most denominations within the new mainline do not consider themselves broad churches.

Despite these shortcomings, the book is a valuable resource. Lantzer's redefinition of mainline and reorientation of the declension narrative are worth this book's publication and the reader's attention.