Research often shows that public opinion is shaped by automatic, non-rational processes—for example, by biases and heuristics stemming from political identity—rather than self-interested reasoning. However, this assumes that reasoning and automatic cognition conflict and that reasoning must be self-interested. Applying abduction, a method of analysis that builds theory by using anomalous cases in the data, we provide evidence of voters’ political opinions in which neither of these positions alone hold. We leverage advances in qualitative methods in the study of motives to analyze semi-structured interview data from 120 American voters collected during the Obama administration. Building on Max Weber’s concept of “value-rationality,” we develop a model of political values in which reasoning is driven by values that resonate with moral intuitions. Central here is the concept from moral psychology of political “Most Sacred Values”—which are values used in political deliberation that resonate with actors’ automatic moral intuitions. People then reason about politics via value-rationality by using values based on political ideology that align with their moral intuitions. We contribute to the public opinion and moral psychology literatures by demonstrating how voters were motivated by political Most Sacred Values to support or oppose the Affordable Care Act (Obamacare).