I think it was the Jones Act but i'll comment on this answer if i'm wrong
The Spanish largely enslaved the native populations and made them act as labor for their new efforts in the Americas.
Following increased pressure from Southern politicians, Congress passed a revised Fugitive Slave Act in 1850. Part of Henry Clay's famed Compromise of 1850—a group of bills that helped quiet early calls for Southern secession—this new law forcibly compelled citizens to assist in the capture of runaway slaves.
