The Fugitive Slave Act was passed by Congress as part of the Compromise of 1850 between Southern slave interests and the Northern Free Soil movement. The Fugitive Slave Act was one of the most controversial provisions of the 1850 compromise and heightened Northern fears of a "slave power conspiracy."
Background
By 1843, several hundred slaves a year were successfully escaping to the North, making slavery untenable in the border states. The Fugitive Slave Act of 1793 required the return of runaway slaves by requiring authorities in free states to return fugitive slaves to their masters. However, many Northern states found ways to circumvent the Fugitive Slave Act. Some jurisdictions passed “personal liberty laws," which mandated a jury trial before alleged fugitive slaves could be moved. Others forbade the use of local jails or the assistance of state officials in the arrest or return of alleged fugitive slaves. In some cases, juries refused to convict individuals who had been indicted under federal law.
The Missouri Supreme Court held that voluntary transportation of slaves into free states, with the intent of their residing there permanently or definitely, automatically made them free, whereas the Fugitive Slave Act dealt with slaves who went into free states without their master's consent. Furthermore, the U.S. Supreme Court ruled in Prigg v. Pennsylvania (1842) that states did not have to offer aid in the hunting or recapture of slaves, which greatly weakened the law of 1793. These and other Northern attempts to sidestep the 1793 legislation agitated the South, which sought stronger federal provisions for returning slave runaways.
In response to the weakening of the original fugitive slave law, the Fugitive Slave Act of 1850 made any federal marshal or other official who did not arrest an alleged runaway slave liable to a fine of $1,000. In addition, officers who captured a fugitive slave were entitled to a bonus or promotion for their work, and any person aiding a runaway slave by providing food or shelter was subject to a six-month imprisonment and a $1,000 fine. Law-enforcement officials everywhere now had greater incentive to arrest anyone suspected of being a runaway slave, and sympathizers had much more to risk in aiding those seeking freedom. Slave owners only needed to supply an affidavit to a federal marshal to claim that a slave had run away. The suspected runaway could not ask for a jury trial or testify on his or her own behalf. As a result, many free black people were accused of running away and were forced into slavery.
Effects of the Fugitive Slave Act
The Fugitive Slave Act was met with violent protest in the North. This anger stemmed less from the fact that slavery existed than from Northern fury at being coerced into protecting the institution of Southern slavery. Moderate abolitionists were faced with the choice of defying what they believed to be an unjust law or breaking with their own consciences and beliefs, and many became radical antislavery proponents as a result. Many Northerners viewed the 1850 Fugitive Slave Act as evidence that the South was conspiring to spread slavery through federal coercion and force regardless of the will of Northern voters. In many Northern towns, slave catchers were attacked, and mobs set free captured fugitives. Two prominent instances in which abolitionists set free captured fugitives include John McHenry in Syracuse, New York, in 1851, and Shadrach Minkins in Boston of the same year.