This paper presents two interrelated arguments: it rethinks conventional understanding of the policy-making process and analyzes an important substantive issue regarding public opinion. The substantive issue involves the public's deep ambivalence toward government reforms: Americans are simultaneously supportive of significant reform and uneasy about expanding government involvement. The critical question is what, if any, impact this public ambivalence will have on policy deliberations. Answering this question requires an analysis of the role of public opinion in policy-making. Investigation of historic as well as contemporary health reform suggests that the impact of public opinion varies, depending on the character of both public opinion and the policy issue. The public's preferences are not especially influential when they are characterized by uncertainty or when an issue is not salient, but strong and sustained sentiment can affect agenda setting, interest group leverage over government officials, and policymakers' formulation of detailed administrative arrangements.