In Trajectory of Power, leading political scientists William Howell and Terry Moe provide a sweeping account of the historical rise of presidential power, arguing that it has now grown to the point where, in the wrong hands, it threatens to subvert American democracy and replace it with a de facto system of strongman rule, whether led by Donald Trump or someone else.

For much of the twentieth century, Republican and Democratic presidents pursued power in very similar ways and almost always within democratic bounds. But Republican presidents since Ronald Reagan, in a transformation that has grown increasingly extreme over time, have gone beyond the "normal" incentives that have traditionally shaped presidential behavior—and still shape the behavior of Democratic presidents—to pursue a presidency of such expansive unilateral power, and with such disregard for basic democratic requirements, that it puts democracy at serious risk.

The book traces this divergence in approach to the backlash of conservatives against the administrative state, and to their epiphany that a war on big government could only be waged through a presidency of extraordinary power. Timely, urgent, and original, Trajectory of Power reveals how the presidency has been profoundly transformed during the modern era—and why it now puts our democracy in imminent danger.