People differ in their lay theories about how and why the financial well-being of individuals changes over time or varies between individuals. We introduce a measure of Causal Attributions of Financial Uncertainty-the CAFU scale-and find that such attributions can be described reliably along three distinct dimensions, respectively capturing the extent to which changes in financial well-being are perceived to be: (a) knowable and within individuals' control due to individual factors such as effort ("Rewarding"); (b) knowable and outside of individuals' control due to factors such as favoritism and discrimination ("Rigged"); and (c) inherently unpredictable and determined by chance events ("Random"). In a sample representative of the U.S. population on various demographic characteristics (N = 1,102), we find that differences in these beliefs are associated with political ideology, revealing a predicted pattern: conservatives scored higher on the Rewarding subscale and liberals scored higher on the Rigged and Random subscales, even when controlling for key demographics. Moreover, we find that these three dimensions predict responses to different policy messages, even when controlling for political ideology. In three preregistered experiments (combined N = 2,560), we observe increased support for various social welfare policies when we highlighted aspects of these policies that are compatible with people's beliefs about financial well-being. Likewise, we observe increased support for political candidates when they expressed their positions in a way that is compatible with people's beliefs. Thus, this work can help better understand drivers of political attitudes and guide in crafting more persuasive policy messages. (PsycInfo Database Record (c) 2022 APA, all rights reserved).