The subject of Hunter Powell's monograph is the debate on church power from around 1640 to 1644, the year the Congregationalist ‘Dissenting Brethren’ entered their dissent in the Westminster Assembly against the Assembly's Presbyterian settlement. The Westminster Assembly has generally been poorly treated in British historiography. Robert S. Paul's 1980 The assembly of the Lord, while a very useful study of the debates, was marred by Paul's own confessional biases and his failure to stray far from Victorian historical scholarship. When discussing the disputes over religion among Parliamentarians in the 1640s, historians have often been unable to escape a conflict model of ‘Presbyterians versus Independents’. In this narrative the ‘Independents’ are pictured as forward-looking tolerationists against the ‘Presbyterians’ drive to impose an intolerant Calvinist theocracy on the British kingdoms. While there is a body of doctoral theses that have challenged this picture, notably the studies of Rosemary Bradley and Carol Geary Schneider, it is rare that a published monograph outside the world of confessional publishing has dealt with these issues. Nevertheless, the subject has received fresh attention in recent years following an important monograph by Michael Winship and the publication of the The minutes and papers of the Westminster Assembly in 2012 under the editorial genius of Chad Van Dixhoorn. Powell's work, which combines the contextual historical theological approach of Richard A. Muller and Carl Trueman with a broadly ‘Cambridge school’ approach to history, is the first monograph to use Van Dixhoorn's monumental edition of the Assembly minutes.

Hunter Powell's book of eight chapters can be divided into three parts. The first two chapters look at the alliances and ideas of the principal godly ecclesiologists from the start of the Long Parliament to before the Westminster assembly was summoned. The middle chapters focus on the confusion generated by the October 1643 debate in the Assembly on the meaning of Jesus' donation of ‘the keys of the kingdom of heaven’ to the Apostle Peter (Matthew xvi) and on the Congregationalists' famous 1644 publication An apologeticall narration. The final chapters focus on the Congregationalists' attempts to define and found their position in the Assembly, the role that continental European and colonial American theologians had in the debates and how the disparate strands of Presbyterianism finally coalesced to lock the Congregationalists out of the Assembly's settlement.

This work is rich in theological detail and Powell takes no prisoners in setting out the fine scholastic distinctions of the early 1640s debates on church power. Throughout the work Powell demonstrates an uncanny knack for finding silent quotations to Assembly members' positions in the surrounding sources. This close reading allows him to tease out the often subtle arguments presented in the debates. One is left with the conclusion that it is no wonder that seventeenth-century contemporaries and modern historians alike have had trouble picking out the distinct positions expounded in the Assembly. Indeed, one gets the impression that the Assembly divines themselves, often finding themselves confronted with issues that had been left unspoken or undefined in Reformed theological discourse, were frequently labouring in a state of confusion to find a consensual position.

Powell's main argument is that the fundamental issue in the debates of the early 1640s was the proper location of church power, expressed, in purest form, in the question of who wielded the power of excommunication. In analysing the dispute, Powell challenges many of the polarising labels that have been used to construct the narrative of ecclesiological debate in the period. In particular he eschews the ‘coarse polarity’ of Presbyterian versus Independent, noting a spectrum of positions within English and Scottish Presbyterianism and substantial differences between the Assembly congregationalists and others branded ‘Independents’ by contemporaries. Histories that focus on pamphlet polemicists such as Thomas Edwards or John Goodwin for understanding the Assembly debates are particularly singled out for criticism. Powell argues that the historian's focus should be on what the Assembly members themselves said and not what was said about them in polemical literature often removed from the debates.

Powell stresses that the various positions in the Westminster Assembly debates on church government were fluid and capable of change based on the arguments presented by opposing positions. He sees the assembly Congregationalists as having the most consistent position but acknowledges that they became more favourable to the role of synods as time went on. Of particular importance is Powell's demonstration that the Assembly Congregationalists distinguished themselves from other ‘Independents’ by arguing that the congregational eldership received its authority immediately and by divine right from Christ. This was similar to the Presbyterian position and contrasted with that of the Separatist John Robinson or the New England pastor John Davenport who saw the eldership's authority as one merely delegated by the people of a gathered congregation. This Assembly Congregationalists' position was shared with John Cotton of Massachusetts and the leading Dutch Reformed theologian Gijsbert Voet.

On the other hand Powell sees at least three types of Presbyterianism in the Assembly. Only one variety held to the ‘ascending’ position commonly understood by historians to be the sine qua non of Presbyterianism, where the higher synods hold their power in a delegated form from individual congregational elderships. Indeed, to the chagrin of the Scottish representatives at the Assembly, the position that won the day was the ‘descending’ position where church power resided in a classis or synod over multiple congregations. According to Powell, the Presbyterian compromise reached in the assembly lent itself to what was essentially a form of prelacy by committee, a position that Powell sees as being in fundamental discontinuity with the continental Reformed tradition.

The crisis of British Protestantism is a valuable ‘thick description’ of the critical debate on church power in the mid-seventeenth century crisis. Powell's reading provides fresh insight into these critical debates and comprehensibly challenges much of the received wisdom on the subject.