2 U.S. Code § 288e - Intervention or appearance
(a) Actions or proceedings
When directed to do so pursuant to section 288b (c) of this title, the Counsel shall intervene or appear as amicus curiae in the name of the Senate, or in the name of an officer, committee, subcommittee, or chairman of a committee or subcommittee of the Senate in any legal action or proceeding pending in any court of the United States or of a State or political subdivision thereof in which the powers and responsibilities of Congress under the Constitution of the United States are placed in issue. The Counsel shall be authorized to intervene only if standing to intervene exists under section 2 of article III of the Constitution of the United States.
(b) Notification; publication
The Counsel shall notify the Joint Leadership Group of any legal action or proceeding in which the Counsel is of the opinion that intervention or appearance as amicus curiae under subsection (a) of this section is in the interest of the Senate. Such notification shall contain a description of the legal action or proceeding together with the reasons that the Counsel is of the opinion that intervention or appearance as amicus curiae is in the interest of the Senate. The Joint Leadership Group shall cause said notification to be published in the Congressional Record for the Senate.