Judicial branch · Landmark case
McGrain v. Daugherty
273 U.S. 135 (1927) · Opinion of the Court
What you should know
This page explains the Court’s holding in plain language, where the official text lives, and what to check next.
Supreme Court findings are not news summaries. The controlling document is the Court’s opinion, plus any concurrences or dissents. Use this profile to understand the holding, then verify language, syllabus, and docket history on official sources before relying on a secondary account.
The Court held that Congress has an implied constitutional power to investigate and to compel witnesses to testify, even though no provision of the Constitution expressly grants it. This power of inquiry is an “essential and appropriate auxiliary” to the legislative function — a legislature cannot write good laws without the ability to gather the information it needs.
Background
The case grew out of the Teapot Dome scandal, one of the largest corruption scandals in U.S. history, involving secret leases of federal oil reserves. A Senate committee investigating Attorney General Harry Daugherty’s failure to prosecute the wrongdoing subpoenaed his brother, bank president Mally Daugherty, demanding testimony and bank records. Daugherty refused to appear. The Senate ordered his arrest for contempt; Daugherty argued in a habeas corpus petition that neither chamber of Congress had any constitutional authority to compel testimony from a private citizen.
A lower court agreed with Daugherty and ordered him released. The Supreme Court reversed, holding that the power to investigate is implied in Congress’s lawmaking authority under the Necessary and Proper Clause — Congress cannot legislate wisely without being able to gather facts, and where it doesn’t already have the needed information, it must be able to compel it from others.
Every congressional hearing that compels testimony today traces its authority back to this ruling.
McGrain is the foundational case behind Congress’s subpoena and investigative power — the same authority invoked in hearings on everything from corporate wrongdoing to executive-branch oversight. The Court did add a real limit, though: the power reaches only matters connected to a legitimate legislative purpose, not a general license to investigate anyone’s private affairs.
Vote and authorship
| Majority | Van Devanter, J. (opinion of the Court) |
|---|---|
| Join | Taft, C.J., Holmes, McReynolds, Brandeis, Sutherland, Butler, Sanford |
| Not participating | Stone, J. |
| Dissent | None |
The power of inquiry — with process to enforce it — is an essential and appropriate auxiliary to the legislative function.
Justice Van Devanter · McGrain v. Daugherty
How it fits in government
Legislative branch
This is the constitutional foundation for every congressional committee’s power to subpoena witnesses and demand documents — a tool used constantly in oversight and investigation work today.
Judicial branch
The Court read an implied power into the Necessary and Proper Clause — a real example of how constitutional powers not spelled out explicitly can still be found essential to powers that are.
Executive branch
The scandal behind this case — a sitting Attorney General’s failure to prosecute wrongdoing — is a real example of why congressional oversight of the executive branch exists at all.
Official records visitors may need
SupremeCourt.gov
Opinions, docket search, rules, and Court information.
Oyez
Case abstract and justice votes.
Opinion text (FindLaw)
Readable public text of the case.
GovInfo · U.S. Courts
Official publications and related federal court materials.
Related research paths
Congressional hearings and subpoenas
How committees actually use the investigative power this case establishes.
Necessary and Proper Clause
Article I’s grant of implied powers to Congress.
Teapot Dome scandal
The corruption scandal that produced this case and reshaped federal ethics oversight.
Landmark cases guide
Other holdings that define the structural powers of Congress.