The question of slavery burst into the public spotlight one summer evening in 1846. Congressman David Wilmot, a Pennsylvania Democrat, introduced an amendment, known as the Wilmot Proviso, to a war appropriations bill. The proviso forbade slavery in any territory acquired from Mexico. Throughout the North, thousands of working men, mechanics, and farmers feared that free workers would be unable to successfully compete against slave labor. "If slavery is not excluded by law," said one Northern congressman, "the presence of the slave will exclude the laboring white man."