US legislation providing for the return of escaped slaves to their masters. After the abolition of slavery in the northern states of the USA, these “free states” became lax in enforcing the first Fugitive Slave Act of 1793. The second Act, part of the Compromise of 1850, introduced more stringent regulations, specifically aimed at the Underground Railroad. Unpopular in the North, it added fuel to the slavery controversy, and “liberty laws” passed by free states to thwart the Act drove the South further towards rebellion. Fugitive slave legislation was finally repealed in 1864.