Much of the research on institutional change shows how systems shift slowly and incrementally. Yet, in the case of former President Donald Trump, change was rapid and radical. In Institutions Under Siege, leading political sociologist John L. Campbell offers new insights for understanding the legacy of the Trump presidency. The book examines Trump’s attack on the ‘deep state’ through the lens of institutional change theory, and demonstrates how he capitalized on tipping points and distinct leadership tactics to inspire, make deals with, and threaten people to get what he wanted. The book also assesses where the damage caused by the Trump administration is most likely to endure and where long-lasting damage was prevented. Sharp and insightful, Institutions Under Siege contrasts existing social science literature to draw attention to the unique significance of tipping points and the characteristics of particular leaders.