Recent years have seen more and more research on campaign effects, likely due to increases in both campaign spending and data quality. This work has approached the electoral campaign from various angles: What types of voters are persuaded by campaigns? Why do certain issues garner so much candidate attention? Why do candidates employ certain tactics? While these questions differ (albeit in some cases very slightly), they are united by an overall goal—the effort to determine if (and how) campaigns matter. The Persuadable Voter and Attack Politics are the latest entries in this line of research and, at their core, both books attempt to solidify our understanding of the relationship between candidate strategy, campaign dynamics, and political outcomes.

Focusing on a campaign's role in voter decision making, The Persuadable Voter is an ambitious undertaking. In addition to analyzing the conditions under which campaigns will influence voters, D. Sunshine Hillygus and Todd G. Shields also seek to leverage this understanding of voter behavior into an explanation of candidate strategy. It is the titular “persuadable voter,” they argue, that leads candidates to highlight certain issues (or conversely, ignore other issues) on the campaign trail.

The book begins with a focus on voters. In particular, Hillygus and Shields argue that in any campaign there are “cross-pressured” voters—voters who must choose between competing considerations. One population of such voters are individuals who identify with one party but disagree with that party on an important issue (for example, Republicans who support stem-cell research or Democrats who oppose abortion). These cross-pressures create a unique possibility for persuasion when a candidate of the opposite party can pinpoint the issue at the heart of a cross-pressured voter's conflict and show that the candidate of the voter's own party is at odds with the voter on this particular issue. Activating these cross-pressures, the authors argue, can lead the voter to vote against their own party in a given election.

Using different data sources and approaching these sources from different directions, Hillygus and Shields show that cross-pressured voters do exist and, subsequently, that when cross-pressure is applied, persuasion is possible. This analysis of voters is both thorough and largely convincing.

The idea of the cross-pressured “persuadable” voter translates easily to candidate strategy. As the authors argue, activating cross-pressures is exactly what candidates seek to do. Relying on archival data and a unique data set of campaign mailings, they trace the way candidates identify potential groups of cross-pressured voters and prime specific issues to activate these cross-pressures. Here, too, they present considerable evidence and make a generally convincing case.

In sum, campaigns seek to win by persuading those individuals most likely to cross partisan lines. This conclusion, the authors argue, is a sharp contrast to existing research that paints campaigns largely as forces that activate the partisan base. While Hillygus and Shields offer some compelling insight into persuadable voters, the potential importance of these voters to any campaign leaves one with questions about the limitations of the underlying mechanism.

Precisely how central, for example, must an issue be to the individual's belief system in order for a candidate to activate cross-pressures? Further, how much activation is needed to bring such a given issue to the forefront? Once activated, how lasting is this persuadability? Do voters retain memory of these cross-pressures from one campaign to the next? Finally, how important is candidate credibility to a candidate's ability to persuade? The intriguing results in The Persuadable Voter offer a strong foundation for future research to tackle these questions regarding mechanism, but also to continue the complex analysis of the relationship between campaign strategy and voter behavior.

While Hillygus and Shields focus on the reciprocal relationship between voter decision making and candidate strategy, in Attack Politics, Emmett H. Buell and Lee Sigelman present an in-depth examination of candidate motivations and behavior. The stated goal here is to “determine the overall negativity of every presidential contest from 1960 to 2004” (p. 26).

Buell and Sigelman approach this task by dividing the campaigns into four categories of competition: the “runaway” campaign, the “somewhat competitive” race, the “comeback” contest, and the “dead heat.” Classifying each campaign from 1960 to 2004 as falling into one of these four categories, the authors undertake an exhaustive analysis of each of these 12 contests. While the focus here is on attacks, in order to situate these attacks in a broader political context the authors fill out each campaign with rich stories of candidate motivation, behind-the-scenes relationships, and complex political machinations.

To consider the timing and content of attacks, the authors rely on a data set of New York Times campaign coverage. This data set is constructed using all published pieces that relate to the campaign, and it includes not only coded news stories but also reprinted press releases, speeches, and campaign advertisements.

This use of the New York Times is notable. As Buell and Sigelman point out, using a mainstream newspaper as a data source makes room for types of campaign discourse (for example, discussions of polls) that are commonly missing in research that relies directly on campaign advertisements or speeches. In addition, the Times coverage allows the authors to simultaneously consider both campaign advertisements and statements made about the candidates by various public figures. This approach provides, arguably, a fuller picture of campaign attacks. Yet this data set is not without limitations—which the authors acknowledge. Since they seek to trace attacks, relying on the Times coverage in effect documents only the attacks that the newspaper deems newsworthy. This approach works to limit the observations in the data set: Not every attack that is transmitted directly to a voter via an advertisement or a speech will be deemed important enough to publish. As the definition of newsworthiness is inherently fluid and journalistic decision making often murky, it is difficult to determine what exactly is left out of this data set and whether these missing observations have any systematic effect on the analysis.

Despite the limitations of this data set, the effort to consider every detail and nuance of campaign attacks is truly breathtaking. Candidate decisions and motivations are documented and placed in the broader historical and political context of each campaign. These rich descriptions not only show who launched an attack but also explain why an attack occurred at a specific point in time, how other political actors responded to the attack, and the eventual political fallout.

Buell and Sigelman are explicit that their goal is to analyze and explain the dynamics of campaigns 1960 to 2004—something they achieve with a superb level of detail. Looking past the goals of this book to the study of campaign effects in general, however, a reader may wonder how the analysis in Attack Politics might translate to future work. The book outlines numerous campaign-specific factors that explain why and when an attack happened in each of the 12 particular cases. While this works well within the scope of the authors' goals, the sheer depth of detail leaves a reader questioning the extent to which the results are generalizable, and wondering what this study implies for future studies of political contests.

Perhaps, as Buell and Sigelman suggest in the conclusion, the most effective translation to future work is not the findings themselves but the general approach of this study—an approach that considers each political contest individually, rather than focusing on broad variables that attempt to unify all campaigns under umbrella explanations. This is a useful method and one that has been very fruitful here. Nonetheless, if we seek to understand campaign effects in general, and candidate strategy in particular, it is likely that both broad umbrella variables and particularized studies such as this one are necessary. To this end, Buell and Sigelman provide a crucial foundation for future work, as it is rich description of the type presented in this book that allows scholars to derive more general hypotheses.