Ever since the rise of Adolf Hitler, mental health professionals have sought to use their knowledge of human psychology to understand - and intervene in - political developments. From Barry Goldwater to Donald Trump, psychiatrists have commented, sometimes brashly, on public figures' mental health. But is the practice ethical? While the American Psychiatric Association prohibits psychiatric comment on public figures under its 'Goldwater Rule', others disagree. Diagnosing from a Distance is the first in-depth exploration of this controversy. Making extensive use of archival sources and original interviews, John Martin-Joy reconstructs the historical debates between psychiatrists, journalists, and politicians in an era when libel law and professional standards have undergone dramatic change. Charting the Goldwater Rule's crucial role in the current furor over Trump's fitness for office, Martin-Joy assesses the Rule's impact and offers a more liberal alternative. This remarkable book will change the way we think about psychiatric ethics and public life.