We explore how political identity affects trust. In particular, we examine the extent to which political identity and objective information shape perceptions about others' trustworthiness. Using an incentivized experimental survey over a sample of the general US population, we vary information about partners' political identity to elicit trust behavior, beliefs about others' trustworthiness, and actual reciprocation. We find that beliefs depend on the political identity of the partner, but they are not always biased against out-groups. This suggests that the cross-party antagonism found in the literature does not necessarily translate into pessimism over what out-groups would do. We also find that people believe others are much less trustworthy than they actually prove to be. We then attempt to correct beliefs by disclosing historical trustworthiness. Subjects' beliefs shift only slightly, suggesting that incorrect stereotypes are difficult to correct.