What is the Wilmot Proviso? Why wasn’t it successful?

The Wilmot Proviso was an unsuccessful 1846 proposal in the United States Congress to ban slavery in territory acquired from Mexico in the Mexican–American War. The conflict over the Wilmot Proviso was one of the major events leading to the American Civil War.

Explanation:

Wilmot Proviso defeated by the Senate for the final time

The Proviso passed the House on multiple occasions, but the staunch slavery supporters in the Senate failed to pass it on multiple occasions.  In short the consensus that the Southern states needed to band together to protect slavery emerged.

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