Congressional Participation in Litigation: Article III and Legislative Standing [Updated November 8, 2019] [open pdf - 1MB]
From the Summary: "Houses, committees, and Members of Congress periodically seek to initiate or participate in litigation for various purposes, such as advancing their legislative objectives, challenging alleged transgressions of their legislative prerogatives, or defending core institutional interests. However, the constitutionally based doctrine of 'standing' may prevent legislators from pursuing litigation in federal court. The standing doctrine requires a litigant seeking federal judicial relief to demonstrate (1) a concrete and particularized and actual or imminent injury-in-fact (2) that is traceable to the allegedly unlawful actions of the opposing party and (3) that is redressable by a favorable judicial decision. The U.S. Supreme Court and the lower federal courts have issued several important opinions analyzing whether--and under what circumstances--a legislative entity has standing to seek judicial relief."
CRS Report for Congress, R45636
Congressional Research Service: https://crsreports.congress.gov/