Leader of the minority party in a legislature WordNet 3.0 & Open English WordNet

The minority leader in U.S. politics is the floor leader of the second largest caucus in a legislative body. Wikipedia

Legislative political position Wikidata

In each of the legislative chambers of the United States Congress—the United States Senate and the House of Representatives—the elected member selected by the members of the political party with the second-largest number of elected members, who serves as principal spokesperson for the members of that party in that chamber and who plays a leading role in creating policies and strategies governing his or her party's business in that chamber. Wiktionary