Wilmot Proviso

In US history, proposed amendment for the prohibition of slavery in any territory acquired by federal funds, first put to Congress by the Democrat David Wilmot in 1846. Although the amendment was never passed, it served as one of the basic principles for the origin of the Republican Party.

Wilmot added his antislavery amendment to a bill, proposed by US president James K Polk, that sought to appropriate $2 million to negotiate a peace settlement with Mexico during the Mexican War (1846–48). Although the House of Representatives approved the amendment the following year, the heavily southern Senate defeated it. The amendment fuelled the debate over the question of slavery in the new territories, but was continually defeated over the years. Slavery was finally banned in all US territories under the Emancipation Proclamation (1862), and enshrined in the US Constitution in 1865 with the Thirteenth Amendment (see Amendment, Thirteenth).