This dissertation is composed of three chapters, each of which explores public opinion formation in American politics: The first chapter, titled Polarization, Alienation, and Trust in Government, introduces perceived polarization (the ideological distance a citizen perceives between the parties) and ideological alienation (the perceived ideological distance between a citizen and the closest party) as process-oriented predictors of trust in government. Using the American National Election Studies (ANES) Cumulative Data File, I find that polarization and alienation both explain trust. I find that these relationships are robust across both time and trust measures. The second chapter, Left Behind: Competitive Nominations and Comparative Candidate Ambivalence, investigates comparative candidate ambivalence (simultaneously holding positive attitudes toward competing general election candidates) as a possible competitive nomination carryover effect on thwarted voters. I draw on motivated reasoning theory to argue that unlike other groups, thwarted voters should gather positive information about both party nominees during the general election due to (1) sour grapes toward their party; and (2) party loyalty-driven pressure to support their party nominee. I test my theory in the context of the competitive 2008 Democratic nomination contest between Hillary Clinton and Barack Obama. Using the 2008-09 ANES Panel Study, I investigate differences in cross-sectional and longitudinal ambivalence between Clinton voters and five other electoral groups. My results are promising, but limited due to low group sample sizes. The third chapter, Who Are the Scorekeepers? Sophisticated Independents and Economic Perceptions, attempts to validate Stimson's (2004) theory that there is a small group of politically well-informed but non-partisan citizens who evaluate the economy objectively. I operationalize these scorekeepers as politically sophisticated independents and divide the ANES sample into four groups: in-partisans, out-partisans, unsophisticated independents, and sophisticated independents. On the micro level, I find evidence that partisans' economic retrospections are biased relative to independents' retrospections. On the macro level, I find that independents mirror the retrospections sample mean particularly well, but partisans are biased. Lastly, I compare each group's predicted probabilities of several retrospection responses across Gross Domestic Product growth levels and find that sophisticated independents' retrospections are most responsive to objective economic conditions.