A study in political psychology identifies four item-based factors of political trustworthiness in the USA: capability, consistency and closeness, egotism and opportunism, and communal commitment. Additionally, a list of items describe epistemic expertise. Together, these elements make up a description of political source credibility in the USA. The current study examines the power of these elements to predict source credibility. Eliciting estimations of likelihood and importance of each item on a Likert-type scale as well as overall estimations of trustworthiness and expertise, the paper presents weighted as well as non-weighted models that predict the likelihood that election candidates are trustworthy, have expertise, and are credible sources for individual respondents. Multiple regression analyses show that non-weighted scales have slightly better predictive power than weighted scales. The findings further provide an example of a data-driven method for applying a general cognitive models of source credibility to specific domains.