Called to Testify: Congressional Oversight of the Armed Forces

Abstract: Committee hearings are a key mechanism by which Congress conducts oversight and shapes defense policy. The expertise Congress chooses to draw upon in these settings can have important implications for the substance of national security choices, the time horizons associated with alternative resourcing investments, and the public’s perceptions of the proper purveyors of defense policy. But few studies have systematically examined which types of witnesses—government civilians, military officers, or outside experts—congressional committees call to testify when investigating defense matters. In a survey of more than 6,500 witness appearances before the House Armed Services Committee from 1975 to 2016, we find that Congress has turned to government civilians and senior military officers in increasingly equal measure when seeking testimony on defense matters. The share of civilian and military witnesses appearing before the House Armed Services Committee remained remarkably stable over time, even when accounting for changes in the committee’s party leadership and increasing occurrences of divided government and rising partisan polarization within Congress. These findings have important implications for the formulation of defense policy and Congress’s underappreciated role in exercising civilian control over the armed forces.