Congressional Debate is essentially a mock congress. A group of contestants, usually called Senators or Representatives (Senators is preferred because it is shorter) debate various bills and resolutions (written by the contestants or the tournament staff) for a certain period of time. Debate cycles between affirmative (pro) speakers and negative (con) speakers. A Presiding Officer (PO) or Chair is elected at the start of debate, and is in charge of keeping order in the chamber.
From the National Forensic League:
From the National Catholic Forensic League: