The same things that provoke social movements also promote institutional pressures for change, shifts in public opinion, and policy change. As a result, disentangling the effects of protest on policy presents an ongoing analytical challenge. If we look, for example, at the volatile and diverse movement against the American war in Vietnam, it is virtually impossible to track clear lines of influence between the volume or disruptiveness of protests covered in the news and spending on the war or casualties produced in battle. At the same time, by reviewing memoirs, archives, and the broader outlines of policy, we know that the movement had longer-term effects, including (minimally), ending military conscription and establishing much stricter political and military tests for long-term commitments of American combat forces overseas. The latter set of constraints, codified as the Weinberger, then the Powell, doctrines, held sway over American military policy from the end of Vietnam until, finally, violated by the current American intervention in Iraq. At the same time, politicians of both parties vigorously try to reassure nervous youth, many of whom are children of the protest generation, that the draft is indeed gone for good. Clearly, the protests against the Vietnam war mattered, though perhaps not exactly in the ways that activists hoped or as much as they dreamed.

Moreover, how can a scholar disentangle the independent effect of protests on policy changes from a host of other causal factors, including the high costs of the war, growing opposition in Congress and public opinion, and the growing expert recognition of alternative means for fighting—or managing—the Cold War with somewhat less direct attention to dominoes. Detailed historical exegesis can help delineate paths of influence; at the same time, examining in detail the complicated trails of policy reforms in the wake of one movement at one time does not neatly translate to a template model for evaluating the impact of other social movements on other policy areas, nor does it allow us to understand when and how social movements matter. These difficulties have led many social movement scholars to avoid the study of policy outcomes altogether, turning their attention to a range of other issues more easily specified.

Neglecting the policy issue, generally the outcome most important to movements, their targets, and their opponents, is to miss the main game. Social movements emerge to make challenges on policy issues, and the belief that they might actually change policies is what produces the hope and fear in organizers, participants, and policymakers that leads them to act as if they might matter. To his credit, Marco Giugni has directly embraced the challenges of assessing the effects of movements on policy, and students of movements and of policy will be provoked, encouraged, and grateful.

Seeking patterns and a general model of influence, Giugni looks at three distinct movement policy areas (environmental protection, nuclear power, and peace) in three democracies, the United States, Italy, and Switzerland. He traces the development of distinct, albeit overlapping, movements in each national context, and the development of each policy area, and then uses time series analyses to test different models of how movements might affect policy. The first section of Social Protest and Policy Change, entitled “Historical Overview,” provides a chapter on the study of policy outcomes of movements, followed by a succinct summary chapter of all three movements in each country, and another on each policy area. The policy summaries focus on easily measured elements of policy, notably budget allocations for all areas, or amount of nuclear power generated for one case.

In the second section of the book, Giugni argues that movement events by themselves are unlikely to have substantial direct influence on policy; instead, they depend upon supportive public opinion and sympathetic policymakers. He advances a joint effects model of policy influence, in which the effects of protest events generate policy reforms in the direction they desire when they enjoy favorable opportunities represented by allies in government and public support. To test his ideas, Giugni has collected time series data on protest events, public policy, public opinion, and partisan balance in each country, no small achievement. Using time series regression, he finds the joint effects model works better than direct effects alternatives in explaining policy change, at least as captured through spending. He finds the strongest influence of social movements on environmental protection, some effect on nuclear power, and much less visible influence on national security policy. He argues that these differential effects across policy areas reflect the varied autonomy that policymakers enjoy on each issue.

Scholars will quibble with both the models and their specifications; indeed, Giugni actively invites debate and correction by providing a very helpful and extensive set of appendices explaining his methodological choices and his data. I appreciate the author's commitment to giving his critics enough data to advance alternative explanations. To take the case of nuclear power in the United States, for example, Giugni suggests that the movement faded before it could exercise much influence, and policymakers turned from nuclear power because of the increased costs of constructing and operating plants. He does not discuss, however, how those costs and difficulties increased partly as a result of stricter safety requirements imposed in response to public concerns. The production of nuclear power increased in the movement's wake, but new plant orders disappeared at about the same time as the movement. In the case of peace movements, which emerge when military spending threatens to increase, it is easy to imagine modest increases in spending as the significant effect of mobilized opposition, albeit not what activists hope for.

We can trace out similarly complicated narratives of each movement's influence to run against Giugni's more parsimonious models, and the ensuing discussion cannot help but shed more light on the difficult, but critical, issue of the effect of movements on policy. Just as William Gamson's (1975) classic Strategy of Social Protest did 30 years ago, Marco Giugni's important book is likely to inspire another long wave of scholarship on the policy effects of movements.