Vigilance Is Not Enough: A History of United States Intelligence

by Mark M. Lowenthal

A broad and deep survey of American intelligence from before the Revolution to the present
Every nation has some sort of intelligence apparatus--a means by which its top officials get needed information on sensitive issues. But each nation does it differently, influenced by its history, its geographical conditions, and its political traditions. In this book, Mark M. Lowenthal examines the development of U.S. intelligence to explain how and why the United States went from having no intelligence service to speak of to being the world's predominant intelligence power almost overnight. He describes how the lack of a tradition of spycraft both hindered and helped American efforts to develop intelligence services during and after the Second World War. He points to the political pragmatism--leading to difficult choices--with which most intelligence directors operated; the constant tension between security and civil liberties in a constitutional democracy; the tension between the need for secrecy and the accountability required for democratic governance; and the way the growing importance of technology changed both the methods and the objectives of intelligence gathering. Far more than simply an episodic history, this book offers an analysis of why American intelligence developed as it did--and what it has meant for the nation's and the world's politics.

Genres: History, Nonfiction

832 pages, Hardcover

First published May 6, 2025

Reviews

[Chad Manske · Rating 5 out of 5]

Mark M. Lowenthal’s “Vigilance Is Not Enough: A History of United States Intelligence” is an authoritative, engrossing survey of American intelligence that manages to be both sweeping in scope and unusually intimate in insight. It is the rare work that can serve simultaneously as a definitive reference, a primer for students and practitioners, and a bracing reflection on the dilemmas of intelligence in a liberal democracy. Lowenthal traces the evolution of U.S. intelligence from the improvised espionage of the Revolutionary era to the extraordinarily complex, technologically saturated system that undergirds American power today. The narrative is not a mere procession of episodes; it is a carefully argued explanation of how a republic that once lacked any formal intelligence service became the world’s predominant intelligence power—and what costs and tradeoffs that ascent entailed. The result is a coherent, compelling story that makes structural change feel as vivid as any operational vignette. What distinguishes this book is Lowenthal’s dual vantage point as both historian and consummate insider. His decades in senior roles at CIA, the State Department’s INR, and on Capitol Hill inform a nuanced treatment of topics that are too often caricatured: the tug-of-war between secrecy and accountability, the persistent friction between security and civil liberties, and the stubborn reality that intelligence is a service function whose value ultimately depends on the proclivities of political leaders. That sensibility gives the book a rare honesty about the limits of intelligence, even as it underscores its indispensability to modern statecraft. Lowenthal writes with clarity, economy, and a steady hand, moving confidently from early American spycraft to the telegraph, codebreaking, and the transformative impact of modern signals and technical collection. He consistently links technological and bureaucratic developments to their strategic and political consequences, making the book as useful for policymakers and operators as it is for scholars and students. For anyone seeking a single volume that explains not just what U.S. intelligence has done, but why it looks and behaves the way it does, “Vigilance Is Not Enough” is indispensable—and likely to stand as the standard history of American intelligence for years to come.