The left-wing climate scientist and political activist Michael Mann resigned on Tuesday from his post as vice provost at the University of Pennsylvania (UPenn). Mann explained in a blog post on Monday that his environmental advocacy work “at times feels in conflict” with UPenn’s institutional neutrality policy. [A]fter police identified Kirk’s killer, Mann joked that “white on white violence has gotten out of hand.”Sen. Dave McCormick (R., Pa.) called for UPenn to take “immediate, decisive action” against Mann following his tirade against Kirk earlier this month. A day after Kirk’s assassination, Mann attacked a New York Times editorial titled, “Charlie Kirk Was Practicing Politics the Right Way.” At one point, Mann reposted a comment likening Kirk to a Nazi. It is unclear whether the University of Pennsylvania leadership forced Mann to resign.