Client Alert: Not Just About Tax Returns: The Supreme Court Clarifies Congressional Subpoena Power—and Its Limitations

When a company finds itself in receipt of a congressional subpoena, it may wonder whether Congress had authority to issue that subpoena. Yesterday, the United States Supreme Court shed light on that question in its decision in Trump v. Mazars USA, LLP, Nos. 19-715 & 19-760. While the decision focused on Congress’s power to subpoena the President’s personal documents, the decision gives some insight into the Court’s thoughts regarding the Legislative Branch’s subpoena power more generally.

Specifically, the Court confirmed that Congress’s power to subpoena is far from limitless, and defenses to congressional subpoenas may exist in some situations. This decision may therefore open up new avenues to object for those who become the subject of a congressional investigation and wish to push back on congressional demands for information.

To read the full alert, please click here.

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© 2026 Jenner & Block LLP. Attorney Advertising. Jenner & Block LLP is an Illinois Limited Liability Partnership including professional corporations. This publication, presentation, or event is not intended to provide legal advice but to provide information on legal matters and/or firm news of interest to our clients and colleagues. Readers or attendees should seek specific legal advice before taking any action with respect to matters mentioned in this publication or at this event. The attorney responsible for this communication is Brent E. Kidwell, Jenner & Block LLP, 353 N. Clark Street, Chicago, IL 60654-3456. Prior results do not guarantee a similar outcome. Jenner & Block London LLP, an affiliate of Jenner & Block LLP, is a limited liability partnership established under the laws of the State of Delaware, USA and is authorised and regulated by the Solicitors Regulation Authority with SRA number 615729. Information regarding the data we collect and the rights you have over your data can be found in our Privacy Notice. For further inquiries, please contact dataprotection@jenner.com.

Client Alert: Not Just About Tax Returns: The Supreme Court Clarifies Congressional Subpoena Power—and Its Limitations

When a company finds itself in receipt of a congressional subpoena, it may wonder whether Congress had authority to issue that subpoena. Yesterday, the United States Supreme Court shed light on that question in its decision in Trump v. Mazars USA, LLP, Nos. 19-715 & 19-760. While the decision focused on Congress’s power to subpoena the President’s personal documents, the decision gives some insight into the Court’s thoughts regarding the Legislative Branch’s subpoena power more generally.

Specifically, the Court confirmed that Congress’s power to subpoena is far from limitless, and defenses to congressional subpoenas may exist in some situations. This decision may therefore open up new avenues to object for those who become the subject of a congressional investigation and wish to push back on congressional demands for information.

To read the full alert, please click here.

Related Locations

© 2026 Jenner & Block LLP. Attorney Advertising. Jenner & Block LLP is an Illinois Limited Liability Partnership including professional corporations. This publication, presentation, or event is not intended to provide legal advice but to provide information on legal matters and/or firm news of interest to our clients and colleagues. Readers or attendees should seek specific legal advice before taking any action with respect to matters mentioned in this publication or at this event. The attorney responsible for this communication is Brent E. Kidwell, Jenner & Block LLP, 353 N. Clark Street, Chicago, IL 60654-3456. Prior results do not guarantee a similar outcome. Jenner & Block London LLP, an affiliate of Jenner & Block LLP, is a limited liability partnership established under the laws of the State of Delaware, USA and is authorised and regulated by the Solicitors Regulation Authority with SRA number 615729. Information regarding the data we collect and the rights you have over your data can be found in our Privacy Notice. For further inquiries, please contact dataprotection@jenner.com.

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