Primary elections evoke differing views about their role in American politics. Reformers in the early twentieth century advocated for primaries to eliminate the corruption they saw in nominating conventions. Early critics argued that primary voters would be less able to recognize the strengths of various candidates and that primaries would prevent parties from nominating balanced tickets. Contemporary critics argue that low turnout results in a primary electorate composed of more extreme voters who nominate more extreme candidates, which contributes to today’s polarized politics. The large social science research on primary elections also provides contradictory evidence about the nature of these elections. Shigeo Hirano and James Snyder’s excellent book provides a few central themes that clarify the influence of primary elections from the beginning of the twentieth century to the early years of the twenty-first century.

Foremost, Hirano and Snyder argue that not all primaries are alike. A dominant theme throughout their book is that the dynamics and outcomes of primary elections vary by the competitive nature of the two parties in a geographic area, whether it is a state, congressional district, or county. The advantaged party, which has the support of a larger proportion of general election voters, will have primary elections with meaningful competition and result in the nomination of highly qualified candidates. Primaries in smaller, disadvantaged parties will have fewer candidates and few qualified nominees. The main reason for this pattern, the authors argue, is the strategic behavior of qualified candidates. High-quality candidates compete in primaries where the nomination is meaningful and promises a strong potential of winning the general election.

Voters also play a role in how primary elections result in the nomination of qualified candidates, according to Hirano and Snyder. Without a partisan cue and frequently with few meaningful issue differences between candidates from the same party, primary voters focus on candidates and their qualities. Primary voters learn about the qualifying experiences of candidates from newspaper endorsements and candidates’ own advertisements. When parties do have significant issue divisions, primary voters respond in kind by supporting primary candidates closer to their own issue preferences. Hirano and Snyder argue that not all primary voters have to focus on the qualifications or issue positions of candidates to produce meaningful primary results. A more astute portion of the primary electorate can swing the results to a meaningful outcome, whether it reflects the quality of the candidates or crucial issue divisions within the party.

The first half of the book examines the historical record for primary elections from their adoption in the early decades of the twentieth century through the 1950s. In the early twentieth century, one-party areas were quite common, not just in the South but also across the northern and western states. Hirano and Snyder demonstrate that primary elections were first adopted in areas of one-party dominance. Primaries introduced electoral competition in these one-party areas, at least for the advantaged party in open-seat contests. Advantaged parties had more primaries with at least two candidates, a larger number of candidates overall, and more competitive outcomes with narrower electoral victories. Primaries in the disadvantaged party lacked these competitive traits, whereas those in areas of more evenly matched parties had a level of competitive primaries somewhere in between that of advantaged and disadvantaged parties.

Hirano and Snyder also tackle questions of how primary elections affect the actions of candidates once they are elected to government office. In chapter 4, the authors ask how primary elections affect the loyalty of members to their party leaders in Congress. Their test case was the split in the Republican Party at the turn of the twentieth century, when congressional party leaders often came from eastern states where party policies protected manufacturing interests with high tariffs, and more populist and agrarian interests were represented by Republicans in states west of the Mississippi. Comparing Republican Party loyalty on roll-call votes from 1890 to 1928, a period that spans the introduction of primary elections, Hirano and Snyder find that eastern Republicans remained loyal to party leaders, but western Republicans deviated from their congressional leaders on issues where their constituents disagreed with the leaders’ positions.

The second half of the book focuses on primary elections after 1950. The period of the 1950s to the 1980s differed from the earlier era by having more competitive constituencies, candidate-centered campaigns, and a strong incumbency factor. By the 1990s, these trends reversed as the era of polarized politics began. Yet some of the basic patterns from the early twentieth century continued. Competition still remained highest in the advantaged party’s primaries. The most-qualified candidates still continued to run in the advantaged party’s primaries and were the most likely to win. And although turnout in primaries was lower than in the earlier era, turnout levels still responded to the competitiveness of the primaries, with higher turnout in open-seat, advantaged party primaries. The authors even find evidence that primary elections are used by voters to punish misbehaving incumbents. Although less than 1% of House incumbents lose a primary election, incumbents caught up in scandals lose 14% of the time.

Chapter 11 of the book tackles the question of primaries in the current era of polarized politics. Hirano and Snyder dispute the idea that primaries cause polarization, simply because they were introduced decades before the recent increase in party polarization. As for primaries contributing to today’s polarized politics, Hirano and Snyder demonstrate that low primary turnout is not a factor, because primary turnout levels are unrelated to the chances of nominating a more extreme candidate. Once again, the competitive nature of the parties matters. More extreme candidates are nominated by both the advantaged and disadvantaged parties, perhaps because voters act sincerely on their issue preferences in cases where the outcome of the general election is governed more by party identification than candidate qualities. However, Hirano and Snyder suspect that strategic primary voters are responsible for the victory of more moderate candidates in areas where both parties have a chance of winning the general election.

On the one hand, Hirano and Snyder’s book reminds us that not all primaries are alike and that future scholarly research should focus on identifying differences in primaries and how these differences matter. An especially important contribution of Hirano and Snyder is their focus on the competitive status of a party as key to the nature and outcome of primaries. High-quality candidates strategically enter open primary races within the dominant party. Meanwhile, primary voters appear to behave strategically by choosing more moderate candidates in areas of two-party competition. Thus, Hirano and Snyder rightfully highlight the importance of electoral competition to both the decisions of candidates and primary voters, something that future scholars should do as well. These authors also demonstrate the importance of considering differences across historical eras and variations in issue and demographic groups within a party’s supporters.

On the other hand, Hirano and Snyder effectively demonstrate that contemporary concerns over differences between open and closed primaries and the role of primaries in partisan polarization may be overstated. With their analyses of primary elections from their inception at the turn of the twentieth century to the polarized politics of the early decades of the twenty-first century, Hirano and Snyder’s book should be of interest to scholars of party politics, electoral politics, and American political development.