Lincoln–Douglas debate is a form of competitive debate between two students. It is practiced mainly in American high schools. It is named for the 1858 debates between Abraham Lincoln and Stephen A. Douglas. The format places heavy weight on logic, ethical values and philosophy.
In cross-examination each side questions the other. The negative side questions the affirmative “to expose logical flaws” in its argument. Within a tournament, each debater argues each side about equally often. The topics set by the National Speech & Debate Association change every two months.