in U.S. history, pre-Civil War laws passed by Northern state governments to counteract the provisions of the Fugitive Slave Acts and to protect escaped slaves and free blacks settled in the North.

Contravening the Fugitive Slave Act of 1793, which did not provide for trial by jury, Indiana (1824) and Connecticut (1828) enacted laws making jury trials for escaped slaves possible upon appeal. In 1840 Vermont and New York granted fugitives the right of jury trial and provided them with attorneys. After 1842, when the U.S. Supreme Court ruled that enforcement of the Fugitive Slave Act was a federal function, some Northern state governments passed laws forbidding state authorities to cooperate in the capture and return of fugitives. In the reaction to the Fugitive Slave Act contained in the Compromise of 1850 (1850, Compromise of), most Northern states provided further guarantees of jury trial, authorized severe punishment for illegal seizure and perjury against alleged fugitives, and forbade state authorities to recognize claims to fugitives. These laws were among the many assaults on states' rights cited as a justification for secession by South Carolina in 1860.