Realizing the ideal of democracy requires political inclusion for citizens. A legitimate democracy must give citizens the opportunity to express their attitudes about the relative attractions of different policies, and access to political mechanisms through which they can be counted and heard. Actual governance often aims not at accurate belief, but at nonepistemic factors like achieving and maintaining institutional stability, creating the feeling of government legitimacy among citizens, or managing access to influence on policy decision-making. I examine the traditional relationship between inclusiveness and accuracy, and illustrate this connection by discussing empirical work on how group decision-making can improve accuracy. I also advance a Generic Epistemic Principle that any evidence-based decision-making procedures must embrace. Focusing on policy-making, I then measure the distance between these standards and the ones actually implemented in U.S. political settings. Psychological research on individual and group decision-making is a source of normative assessment for existing policy judgment, but it neither rationalizes nor legitimates the actual and typical processes used in U.S. institutions of political decision making. To establish this point, I focus on one characteristic government institution—the U.S. House of Representatives Committee on Science, Space, and Technology—that displays deliberative processes at odds with the sciences they advocate, and with the Generic Epistemic Principle. I explain this discouraging condition in terms of several inveterate factors in U.S. politics: a limitlessly money-driven and endless campaigning process that effectively forces elected representatives to align themselves with money and vote strategically, the use of procedural arrangements known to make people feel politically included when they are not, and the unresponsiveness of a majoritarian (vs. consensus) democracy.