The American experiment tests whether a democracy—a government set up for the people and by the people—can succeed. Our history so far answers that democracy can realize significant achievements though not without great effort, frequent missteps, and wrenching change. One key to American success has been the country’s ability to admit problems and change course. And central to that process has been the U.S. Congress which, throughout American history, has investigated, exposed, and responded to our deepest crises, concerns, and scandals.

This book recounts American history through the crucible of investigations conducted by Congress—national inquiries which bared our faults as a society, exposed failings by our government, and amplified demands for change. Those inquiries—like our democracy—weren’t perfect or always just; they include ugly chapters that pushed our democratic values to the breaking point. But congressional investigations also gathered evidence for later generations to ponder and debate; fostered a public square that values factfinding; and, along the way, helped shape American history itself.

When Congress investigates, it exercises its power to conduct an in-depth look into matters of public concern and obtain the factual information needed to make informed decisions about how to respond. That is called “oversight.” As the Supreme Court explained in a case upholding Congress’ power to subpoena information, the “‘power of inquiry—with process to enforce it—is an essential and appropriate auxiliary to the legislative function.’” The Court observed that “[w]ithout information, Congress would be shooting in the dark, unable to legislate ‘wisely or effectively.’” It affirmed Congress’ authority to conduct broad examinations, noting that the legislature’s power to investigate “encompasses inquiries into the administration of existing laws, studies of proposed laws, and ‘surveys of defects in our social, economic or political system for the purpose of enabling the Congress to remedy them.’”

While Congress’ investigative track record is not without flaws and gaps, and at times has been excessively partisan or abusive, Congress has an unrivaled ability to shine a national spotlight on issues that matter to the American public. Congress is also uniquely positioned to tackle daunting problems in both the public and private spheres, obtain information from a broad spectrum of individuals and entities, and command public and media attention. At its best, Congress has provided hearings and reports that helped inform and crystallize public views about important events in the past and what should happen going forward.