At a recent conference attended by Lutheran theologians and ethicists of three Lutheran churches—ELCA, LCMS, and NALC—a professor from one of the ELCA colleges told me she used a book or two of mine in her classes even though she disagreed with me on several major ethical issues, one of which was no doubt my commitment to the traditional Lutheran notion of marriage. But, she said, our disagreement was on “second-order issues,” which ought not be church-dividing. We agree on justification, she offered, and that was sufficient. That opinion was often marshaled as an argument to keep the ELCA together precisely by those who wanted to change its teaching and practice on important ethical matters.
 Since she was being gracious to me, I was not churlish enough to argue with her even though I disagreed strongly with her remark. I thanked her for increasing the royalties from my books and laughed. The authors of this volume, whose essays were first heard as lectures at The Center for Catholic and Evangelical Theology’s annual summer conference in 2010, could not duck the issue so easily. They were charged to address the topic of the conference itself—whether some ethical issues have been and ought to be church-dividing.
 As to the empirical question of whether churches have divided over ethical questions, several authors catalogue the historical instances in which such division has taken place. Beth Barton Shweiger, in the book’s second essay, examines how slavery and race were church-dividing issues for the churches before, during, and after the Civil War. Presbyterians, Baptists, and Methodists experienced painful division in that period. (She mistakenly claims that Lutherans avoided such a split (16), but in fact the United Synod of the South split from the northern Lutheran churches in the Civil War and did not enter the United Lutheran Church until 1918.) Indeed, she observes that for the churches of that time division over the ethical issue of slavery was “as natural and necessary as division along doctrinal lines.” (20)
 The last two chapters of the book also survey historical examples of organizations and churches probing the question of whether doctrinal agreement and communion can be sustained without ethical consensus. James Buckley argues that the proceedings of Evangelicals and Catholics Together (the organization put together by Richard John Neuhaus and Charles Colson in 1984) can serve as a model for learning how to be morally divided, though he admits that the representatives of the Catholic and evangelical traditions involved in those discussions reached a good deal of consensus on both doctrine and morals. He notes how their sixth statement in 2006 comes to the conclusion that “support for a culture of life is an integral part of Christian faith and therefore a morally unavoidable imperative of Christian discipleship.” (107) The lingering ethical disagreements between the leaders of the ECT initiative were infinitesimal compared to those that have emerged in the mainline Protestant churches.
 The last essay by Michael Root traces ecumenical dialogues on ethical issues by many different denominations, but focuses on those of the Anglican-Roman Catholic International Commission, which grappled in the 1990s with both general ethical principles and more specific moral issues. He notes that there seemed to be agreement on general principles among the Anglican and Catholic participants, but the closer they got to specific issues, the more disagreement emerged. Disagreement over the latter prevented any further move toward union. This leads Root to the conclusion that “Ecclesial communion requires not only a common vision of the Christian life, but a common recognition that the rules and practices of the churches adequately embody that vision and sufficient unity in those rules and practices to permit common pursuit of that life.” (133) In short, unity within and among churches cannot avoid those questions we call ethical.
 I have termed those three essays “empirical” or “historical.” They analyze historical precedents and come to the conclusion that some ethical disagreements are so serious that they certainly cannot be termed “second-order.” Disagreements about them are indeed church-dividing. The rest of the essays are more normative in character, i.e., they argue that theological and ethical matters ought to be powerfully connected.
 Frederick Christian Bauerschmidt challenges the 60’s theme that “doctrine divides; service unites.” On the contrary, he argues, knowing and doing are mutually interdependent in the Catholic tradition, but also in the Protestant. He notes that Barth presents “a unified treatment of doctrine and ethics” in the Church Dogmatics. (31) He gives a number of examples in the history of the church of breaks in unity on account of ethical disagreement. Toward the end of his essay he brings up the issue of homosexual conduct that vexes so many denominations. He contends that we cannot slough that issue off as “second-order” because “our views on homosexuality imply and should be informed by our convictions concerning theological anthropology, or the nature of the authority of Scripture, or whether we believe there is a natural law and how we understand it in relation to culture.” (41)
 The Presbyterian Joseph Small, though recognizing that the differences in his church over ordination and marriage of partnered gays are and should be church-dividing, hopes against hope that a confessing movement within the PCUSA will bring the church back to the classical doctrines and practices on these matters from which it is currently straying. Susan Wood argues that unity in sacramental life implies unity in the moral life. She cites the substantial portion of Colossians that lists the ethical requirements of the baptismal life, which include a rather strict governance of sexual life along with other imperatives. (73)
 Two Lutherans round out my account of the essayists. Robert Jenson is clear that disagreement on some serious moral issues ought to be church-dividing. “I will argue that the unbroken unity in Christ of baptized believers divided in moral discipline or public moral witness obtains at the same level as does the unity of baptized believers divided in doctrine.” (2) He grapples with two further questions: which moral issues are that serious and what should we do about it?
 He answers the first by arguing that the emerging differences in the churches over the nature of Christian marriage, to which the debate over homosexual conduct has quickly morphed, are very serious. Differences on this matter will compromise church unity deeply because “disagreement about the ontological status of what was once called marriage is simultaneously an ethical and a doctrinal disagreement: it is a disagreement about a fundamental structure of human being as Scripture describes it, a structure established in Christ’s relation to the church.” (8)
 Jenson is less clear about what defenders of classical teaching and practice should do when their churches go astray. Though they cannot countenance what their churches have done, “need they immediately depart from a body they deem morally heretical at this point? The call is even trickier.” (11)
 David Yeago is on the same page as Jenson. The title of his essay pretty much summarizes his argument and the overarching argument of the whole volume: “Grace and the Good Life—Why the God of the Gospel Cares How We Live.” (77) In his essay he agrees with Jenson that “we cannot agree about Christ if we disagree about substantial matters of moral teaching.” (78) He then fleshes out his argument by pointing to the crucial importance of divine law in creation, the imago dei (our creation in the image and likeness of God), and in the Christian life. “Substantial agreement about Christ must involve substantial agreement about the law,” and in his view the ELCA has departed from authentic teaching of the law, and, therefore, of Christ.
 He follows Jenson on another matter—his uncertainty about whether adherents of traditional Christian moral teaching should break unity with a revisionist church. When he wrote this essay he called the situation in the ELCA one of “impaired communion,” and counseled that dissenters should protest within the denomination, much as Small recommends to his fellow Presbyterians. However, nothing clears up uncertainty about staying or leaving more quickly than being dismissed from one’s job at an ELCA seminary in spite of being the most distinguished systematic theologian in its seminaries. Yeago is no longer in impaired communion in the ELCA. He is the NALC’s systematic theologian in its new seminary that is in cooperation with the Anglican Church of North America’s Trinity School for Ministry in Ambridge, Pennsylvania.
 All the authors in this volume agree on the general principle that Christian doctrine and central moral teachings and practices cannot be divided into “first-order” and “second-order” issues. What would one expect of an organization that is aiming at being orthodox, evangelical, and catholic? A majority of the authors take the next step and argue that the Christian doctrine of marriage is one of those central moral teachings that cannot be altered without threatening the unity of the church.
 They are right. Each mainline denomination is in the process of dividing precisely over differences in Christian teaching on the nature of marriage, though that was not where the debate began. In each denomination the difference initially seemed to focus on the legitimation of homosexual conduct, but in a flash, expected by neither revisionists nor traditionalists, the debate was quickly transmuted into one about the nature of marriage. For the ELCA the practice of homosexual marriage has dictated a change in the Christian doctrine of marriage. The ELCA has a male bishop “married” to another man, and it is highly unlikely that his actions will be criticized for violating classical Christian teaching, mainly because the ELCA has de facto departed from that teaching. Indeed, the former Presiding Bishop of the ELCA promised that the gay bishop would never again be “rebuked.”
 Marriage practice in the ELCA is no longer guided by the theological conviction that marriage is a permanent “one-flesh union” made up of two complementary beings who together constitute the image of God, and which is oriented toward procreation. It has departed from the Great Tradition on a central Christian theological and ethical teaching and has provoked schism, it being the schismatic party.