Transgressive leadership, especially in politics, can have significant consequences for groups and communities. However, research suggests that transgressive leaders are often granted deviance credit, and regarded sympathetically by followers due to perceptions of the leader’s group prototypicality and identity advancement. We extend previous work by examining whether these perceptions additionally play a role in rationalizing the transgressions of a leader and whether deviance credit persists after a leader exits their leadership position. The present three-wave longitudinal study (N = 200) addresses these questions using the applied context of the 2020 US Presidential election. Across three survey waves administered during and after Donald Trump’s election loss, Republicans perceived three transgressive behaviors (sharing false information, nepotism, and abuse of power) as less unethical when committed by Donald Trump than when the same behaviors are viewed in isolation. Perceptions of Trump’s identity advancement, but not his group prototypicality, predicted the extent to which Republicans downplayed the unethicalness of his transgressions. Decreases in identity advancement across time were also related to increases in perceptions of Trump’s unethicalness. Implications for the social identity theory of leadership, subjective group dynamics, and the broader consequences of deviance credit to transgressive leaders are discussed.