Ever since George Gallup developed his vision for public opinion in his book, The Pulse of Democracy, polls have become the dominant way of taking the temperature and feeling the "pulse of the nation." All of these prototypical polling reports and press releases presumably tell us something about the "state of the nation," the "mood" and direction of the country, and the performance of the President, the Congress, the economy, and the two major political parties. However, the well-established indicators of the changing "pulse of the nation" are seriously contaminated by measurement error and are therefore highly misleading, widely misinterpreted, and often misunderstood by the public, the press, and the powers that be. Using multiple case studies, the authors document the fundamental problems facing scholars, journalists, and public policy makers who rely on such indicators to monitor and interpret changes in American public opinion. The psychological meaning-and-interpretation of most public opinion indicators is continuously shifting in response to real-world events covered in the mass media and, as a consequence, these indicators cannot be compared systematically over time. Instead, apples are often being compared with oranges. Even when the wording of questions remains the same, their meaning and interpretation can shift over time, producing comparability problems. This book includes a review and integration of rival explanations of changes in American political attitudes and public opinion from prosaic accounts routinely offered in the press by pollsters and journalists, to more rigorous theories of mass media agenda-setting, cognitive-psychological "priming," changing "mood" dynamics and other rival models. The book concludes with a discussion of the implications of its findings for the measurement of public opinion and the paradigm of survey research, raising the fundamental epistemological question of whether we can ever ask the same survey question twice and whether our questionnaires and survey instruments are a thing of the past.