It is often said that the “devil is in the details,” and perhaps no book better illustrates this idiom in American politics than Amy McKay’s Stealth Lobbying. In this book, McKay argues that much of the influence achieved by lobbyists in Congress is hidden from public view and occurs at particularly pivotal moments during lawmaking processes. To McKay, “stealth lobbying” consists of “hidden requests for low-salience legislation” (p. 9). Using a variety of datasets that delve into the details of congresspersons’ schedules and lobbyists’ activities, McKay finds compelling evidence that stealth lobbying, particularly fundraising activities, affected the content of the Patient Protection and Affordable Care Act of 2010. By delving into the details of the act and uncovering previously undocumented means of influence, McKay suggests that previous searches for lobby influence in Congress were constrained by a lack of data and so were akin to searches for “lost keys in the light of [a] streetlamp” (p. 7); finding influence requires looking into the “dark” (p. 60). McKay shines a light on the details of Washington lawmaking and finds more than lost keys. She reveals a proverbial “devil”: special-interest influence.

Three themes underlie McKay’s examination of stealth lobbying. They help determine, in McKay’s argument, why stealth lobbying is an effective yet generally unknown tactic in Congress. First, lobbyists achieve more influence when the public salience of an issue is low. The lack of salience provides reelection-seeking legislators the cover to work with lobbyists. Why would legislators work with lobbyists? The answer to this question is the second theme in McKay’s argument: lobbyists achieve influence because they “make themselves useful” to lawmakers (p. 10). Lawmakers are said to be under immense pressure to fundraise for both their own and their colleagues’ reelection efforts, and lobbyists facilitate the bundling of donations that do not need to be reported to the public (pp. 97–101). They also provide information to legislators. Although these two themes help explain the empirical findings presented throughout the book, McKay’s third theme shows why previous studies looking for the influence of money in Congress yielded null findings for the most part. According to McKay, prior research struggled to find an effect of money on policy because of methodological limitations, intentional concealment of activities on the part of legislators, the prevalence of negative lobbying, and the “inverse pull” (p. 21) of access and influence; that is, lobbyists gain the most access to the least powerful legislators. In finding evidence for the effectiveness of stealth lobbying, McKay brings to light an unknown form of lobby influence.

Stealth Lobbying includes four chapters that present empirical findings. The first one examines the daily schedules of 11 members of Congress. Although these 11 members are not representative of the entire Congress, they vary in terms of the explanatory variables of most interest to McKay and include legislators (e.g., Max Baucus) who played prominent roles in reforming health care. The schedules were released voluntarily by the members. Regression analyses show that members granted more meetings to lobbyists who made donations or organized fundraising events and who were active on bills the member had sponsored. Interestingly, members with more prominent committee assignments granted access to lobbyists less often in general. McKay indicates that her analysis is the first to examine congresspersons’ daily schedules.

Next, McKay turns to the political action committees (PACs) that lobbyists help direct. The Patient Protection and Affordable Care Act was developed during a time of “maximum campaign finance reform” (p. 63): after the implementation of the House Leadership and Open Government Act that banned personal gifts from lobbyists but before the Supreme Court’s Citizens United decision. Hence, during the act’s development, legislators could not rely on soft money, and lobbyists had to rely only on direct contributions and fundraisers to show support or build relationships. By painstakingly piecing together lobby and donation records, McKay builds a dataset consisting of contributions from both lobbyists and the PACs they control and, to avoid selection bias, the senators to whom they might have given contributions. The resulting dataset is the first to quantify how lobbyists direct PAC donations, including their timing and size. The related analyses, which all are based on multiple hundreds of thousands of observations, show that health care lobbyists gave or authorized more donations than other lobbyists in general during the drafting of the Affordable Care Act (ACA) and that these donations were disproportionately channeled to members of the Senate Finance and Health, Education, Labor and Pensions (HELP) Committees.

The final two empirical chapters of Stealth Lobbying contain some of the most compelling evidence of lobby influence presented in the book. McKay argues persuasively that introducing amendments is a low-cost activity for members of Congress. She also argues that amendments often provide organized interests with private or particularistic benefits. Hence, given the tremendous pressure for legislators to raise funds, the institutional context encourages rent-seeking (a term McKay does not use). Ultimately “members of Congress are skilled at framing their amendments in a defensible way… [but lobby groups] know they are the result of the lobbyists’ efforts” (p. 105). McKay calls these amendments “microlegislation” (p. 9).

Fortunately for McKay, who was working as a congressional fellow during the ACA’s development, the chairman of the Senate Finance Committee sought comments from the public about various options for reform. As a result, McKay was able to garner the requests or positions of nearly 900 lobby groups. Using software designed to detect plagiarism, she identified more than 200 instances in which a member of the Finance Committee introduced an amendment that was advocated expressly by a lobby group. Analyses reveal that “when a lobby group hosts a fundraising event for a senator, that senator is more likely to offer an amendment requested by that same group” (p. 126). But did any of these amendments appear in the Finance Committee’s final version of the law? Yes: in fact, campaign contributions from lobbyists or PACs were positively associated with amendments appearing in the committee’s final version of ACA. This effect is masked by the overall lobbying activity of amendment supporters, which helps explain why studies that examined only lobbying activities failed to find evidence of influence.

In general, Stealth Lobbying is a work of tremendous scholarly value. McKay delves into the details of congressional lobbying to a greater extent than nearly any other study except for, perhaps, her previous publications on microlegislation. “Stealth lobbying” and “microlegislation” are original concepts that belong in courses and textbooks on lobbying and interest groups. Although articulating these concepts are themselves valuable contributions, McKay’s book is particularly noteworthy because of the consistent statistical evidence it presents for the influence of money over policy. She is correct to highlight the inconsistent findings of previous studies on influence and argues persuasively that finding such evidence requires delving into the details of legislation. (Nearly all the datasets are presented for the first time.) Fortunately, the most powerful legislators appear to be less moved by lobby groups. This “inverse pull” narrative can provide insight into institutional reforms but is the least developed of the theoretical narratives and is tested less often.

Still, questions remain. In the final chapter, McKay does not sufficiently address the generalizability of her findings nor possible confounders. Surely, although she provides evidence that the content of the ACA was influenced by lobby groups, she presents her results as if they may apply to microlegislation of all types. At present, McKay assumes that all microlegislation is equally nonsalient. (This is likely a fair assumption in the context of the ACA, but is microlegislation ever salient at all?) It especially remains to be seen how the emergence of “super PACs” in a post–Citizens United world affects the efficacy of stealth lobbying. Lobbyists no longer control funds as exclusively as they used to, so their individual influence on legislators might have weakened. Finally, it is worth considering how lobbyists’ use of outsider tactics may have affected the trends McKay finds. In an article that examines group activity on the Medicare reforms of 2003, Richard Hall and Molly Reynolds find that lobby groups targeted the constituencies of specific legislators with advertisements and timed their efforts strategically. It remains to be seen whether the insider techniques that McKay documents are affected by any outsider techniques that occurred during the ACA’s development. Nevertheless, the book’s merits far outweigh any of these issues, and that is why the book is likely to be cited by scholars of lobbying for decades to come.