Scholars assume that citizens perform better when they know pertinent facts. Factual beliefs, however, become relevant for political judgments only when people interpret them. Interpretations provide opportunities for partisans to rationalize their existing opinions. Using panel studies, we examine whether and how partisans updated factual beliefs, interpretations of beliefs, and opinions about the handling of the Iraq war as real-world conditions changed. Most respondents held similar, fairly accurate beliefs about facts. But interpretations varied across partisan groups in predictable ways. In turn, interpretations, not beliefs, drove opinions. Perversely, the better informed more effectively used interpretations to buttress their existing partisan views.

Scholars of political behavior increasingly embed experimental designs in opinion surveys by randomly assigning respondents alternative versions of questionnaire items. Such experiments have major advantages: they are simple to implement and they dodge some of the difficulties of making inferences from conventional survey data. But survey experiments are no panacea. We identify problems of inference associated with typical uses of survey experiments in political science and highlight a range of difficulties, some of which have straightforward solutions within the survey-experimental approach and some of which can be dealt with only by exercising greater caution in interpreting findings and bringing to bear alternative strategies of research.

Duverger's law is an unusually simple and specific elaboration on exactly how political institutions “matter”: It proposes that plurality rule elections result in two-party competition. Canada is commonly thought to violate the law at the national level, but to match its predictions at the district level, and thus not to constitute a genuine counterexample. In fact, analysis of a vast data set of Canadian election returns reveals that these elections are multicandidate events, district by district, year after year. An explanation for this multipartyism may lie in the complicating factor of federalism, because Canadian provinces often feature strikingly different national and provincial party systems. Generally, the Canadian case illustrates that theories relating party systems to electoral law but not to other institutions are unrealistically parsimonious.

IntroductionIn recent years, the availability of online source material and online papers has increased instructors' concerns regarding plagiarism in the classroom. Many instructors do not realize, however, that the digital revolution has also created a niche for fast and (at least somewhat) reliable plagiarism-detection software.