Ideas of the Liberal Party offers a vigorously argued and compelling revision of early Victorian political culture. The book's core argument is that “a coherent and recognizable Liberal Party existed before 1860” (6) and that this party was self-defined, self-conscious, disciplined, and organized around a core set of shared political principles. Coohill does more than simply push John Vincent's classic argument about the genesis of the Liberal Party back in time. He argues, instead, that the “Liberal Party” of the 1830s and 1840s was stronger, more durable, and more coherent than Vincent's later, more vulnerable “coalition of convenience” (Formation of the Liberal Party, 1857–1868 [1966], 258). Indeed, Coohill goes so far as to claim that his early Victorian Liberal Party was stronger even than the Gladstonian Liberal Party of the 1870s and 1880s. This is a bold thesis, made all the bolder by the fact that it flies in the face of a large body of scholarship dedicated to drawing out the cultural and political barriers that stood between Whigs, liberals, reformers, radicals (romantic, utilitarian, and other varieties), and Irish repealers during the early Victorian period.

The early chapters of the book are dedicated to an analysis of the political labels and language used by parliamentarians when presenting themselves to their constituents and to each other. Coohill argues that the early Victorians had a clear sense of what it meant to describe oneself as “liberal” and an equally firm grasp on the nature of political parties. Moreover, he demonstrates that the term “Liberal Party” was widely used to describe the parliamentary opposition to Peel and Wellington from 1834. In a fascinating discussion of the role played by parliamentary guides in presenting information on MPs to the public, Coohill charts the increasingly widespread use, especially from 1847, of the term “liberal,” and the decline of competing labels (such as “reformer” and “whig”), to describe the political affiliations of non-Tory entries in Dod's Parliamentary Companion. But these parliamentarians were Liberals in more than just name. Liberal Party MPs, Coohill maintains, expressed a consistent political creed, which emphasized political reform and trade liberalization, in a number of different contexts. This creed was promoted in public declarations of political principles, in correspondence with constituents, and in private communications between parliamentarians. Liberal MPs also voted in accordance with this creed, not least because the party had by the 1840s developed a fairly strong regime of party control and discipline. Coohill finds evidence for all of these claims in the papers of numerous backbench MPs. If Coohill's use of these papers is not quite as novel as he suggests—Coohill repeatedly emphasizes that his study eschews the study of both cabinet-level high politics and constituency-level popular politics and looks instead to the parliamentary forgotten middle rank—it nonetheless is a great source of strength for his argument.

If Ideas of the Liberal Party devotes considerable attention to the intersections of political language and identity, it is equally concerned with political structures and behavior. The second half of the book consequently seeks to demonstrate Liberal Party cohesion in the House of Commons by exploring liberal responses to, and voting on, issues ranging from the abolition of the church rates to the promotion of free trade. Coohill here argues that Liberals rallied around a core set of political priorities (which he is careful to differentiate from what Jon Perry terms a “liberal value system”) that held the party together despite the many small disagreements of its members. Liberals broadly agreed that national institutions should be used for the public good, for instance, and therefore argued that the surplus revenues of the church of Ireland should be applied to general purposes, including the funding of the Irish National Board of Education. The Maynooth Grant was more divisive, but nonetheless became a “defining issue” (162–69) for the Liberal Party. But unified Liberal political behavior extended far beyond Irish policy. Free trade was perhaps the most important unifier. By 1841, Liberals were so overwhelmingly supportive of free trade that 289 out of 307 Liberal MPs could vote in favor of Russell's 1841 Sugar Duties motion. Moreover, Coohill shows that a significant number of the 18 Liberals who opposed the motion did so out of the conviction that free trade in sugar would increase the slave trade. These Liberal critics of the motion, many of whom had voted in favor of trade liberalization in 1839, were exercising their Liberal prerogative to “considered inconsistency.”

There is a great deal to admire about Coohill's revisionist account of early Victorian politics. The argument is forceful and direct; the evidence is fulsome and well used; the terms of investigation are clearly and reasonably defined; the historiography is generously mapped out. At the same time, the absence of countervailing evidence can make Coohill's argument feel forced, overly schematic, and perhaps even manipulative in places. Expressions of distrust and even outright opposition among “liberal” subgroupings were very common during this period. For every parliamentarian who publicly claimed to belong to a “Liberal Party,” there was another who disavowed the party connection altogether. William Molesworth claimed, for instance, that he would stand against the devil himself if he showed any inclination to Whiggism. Yet such expressions of factionalism are wholly absent from this study. This disharmony was most prevalent in discussions of social and administrative reform—topics that do not feature in Coohill's discussion of the Liberal political creed. Liberal groups did indeed find common cause in trade, Ireland, and religion, but did this common cause extend beyond these issues? Beyond this overselectivity, the book's methodology is open to question in two ways. First, Coohill claims: “[E]vidence unearthed in the archives does not include strong denials of the existence of the party. Neither does it offer detailed descriptions of the party. This strongly implies that the existence, nature, and purpose of that party were already understood” (205). Or it might equally imply that the party did not exist at all. Second, and finally, there is a certain circularity to Coohill's argument. Did the Liberal Party exist because a set of parliamentarians behaved and presented themselves in certain ways? Or did these parliamentarians behave and present themselves in certain ways because they belonged to the Liberal Party? Coohill seems to suggest both.