When Congress Comes Calling: The Limits of Executive Privilege
A new edition of our popular guide to congressional oversight, updated in 2025.
Often called the “first branch among equals,” the U.S. Congress serves as a crucial check on the executive and judicial branches. The goal is easy to understand, but in reality, the oversight process is incredibly complex. Effective oversight requires a strong understanding of the resources and powers available to Congress, as well as potential nuances (both practical and statutory) that oversight practitioners should be prepared to address.
When Congress Comes Calling: A Study on the Principles, Practices, and Pragmatics of Legislative Inquiry is designed to provide Members of Congress and their staff with this information. This new edition, from POGO and Jenner & Block’s Congressional Investigations practice, updates the 2017 guidance provided by Morton Rosenberg and The Constitution Project.
The newest edition of When Congress Comes Calling reflects how much congressional oversight has evolved in recent years.
Oversight is one of Congress’s core constitutional duties. It is vital to maintaining an accountable, ethical, and effective federal government. Through rigorous, fact-driven inquiries, Congress can uncover systemic waste, fraud, corruption, mismanagement, and abuses of power.
The newest edition of When Congress Comes Calling reflects how much congressional oversight has evolved in recent years. It incorporates analyses of recent legal developments and modern investigative practices, along with insights from Democratic and Republican experts who have served in senior roles across the legislative and executive branches.
This resource arrives at an important moment, offering Congress timely, practical, and bipartisan guidance to strengthen its oversight work in the years ahead.
Along with case studies, it contains chapters on:
- adapting legislative inquiry to the present day;
- the purposes, powers, limitations, and practicalities of congressional oversight;
- the powers and tools available to Congress for conducting investigative oversight;
- the mechanisms for enforcement of Congress's investigation power;
- the process of conducting investigative oversight proceedings;
- the breadth of Congress’s authority to access information;
- why common law privileges available in court may not shield witnesses from complying with committee information demands;
- lessons Congress can take from executive branch investigations;
- the rights and roles of the minority party and individual members during the investigatory process;
- the role of inspectors general as Congress’s eyes and ears inside government departments and agencies;
- speech or debate protections;
- Congress’s extraterritorial investigative powers;
- Congressional interventions into agency decision-making;
- the Congressional Review Act;
- oversight of federal judges;
- responding to congressional inquiries; and
- the Constitution and oversight of the administrative bureaucracy.
POGO has long supported Members of Congress in their critical oversight responsibilities. We are pleased and proud to offer this new edition of When Congress Comes Calling, updating the 2017 edition by The Constitution Project. To learn more about the additional support POGO provides, please visit or reach out to our Congressional Oversight Initiative.