Which of the following best describes the Wilmot Proviso? The Wilmot Proviso was a document about the future of slavery in all territory acquired from Mexico. The Wilmot Proviso was an outline of the procedures for new territories to become states. The Wilmot Proviso was a military strategy that explained how to win the Mexican-American War. The Wilmot Proviso was a campaign document to help elect Congressman David Wilmot.