We have witnessed an alarming deterioration of truth in democracies around the globe, especially in the political arena. This paper describes a proposed intervention, the Pro-Truth Pledge (PTP), which combines behavioral science research with crowd-sourcing to help address this problem. The PTP asks signers – private citizens and public figures – to commit to 12 behaviors that have been shown to be correlated with an orientation toward truthfulness. Pledge mechanisms have been shown in other contexts to lead private citizens to engage in more pro-social behavior. For public figures, the PTP offers specific incentives to behave in concordance with the Pledge, with rewards in the form of positive reputation for honesty and truth-telling, and accountability through crowd-sourced evaluation and potential aversive consequences contingent upon deception. A study conducted on the PTP has demonstrated its effectiveness in reducing the sharing of misinformation on social media. These preliminary findings suggest that the PTP may be an effective intervention for addressing at least some of the problems caused by fake news and post-truth politics.