FUGITIVE SLAVE ACT OF 1850

This law enraged and at the same time made abolitionists fearful of being put in jail. Suddenly law enforcement personnel were required to aid the capture and return of all runaway slaves, or risk a $1000 fine. Any citizens providing food or shelter to fugitive slaves were also liable for a $1000 fine and 6 months in jail. It is said that this law inspired Harriet Beecher Stowe to write Uncle Tom’s Cabin. Sojourner Truth and others considered it more of a nuisance, and made it a little more dangerous, but did not diminish their commitment to the cause of justice.

http://en.wikipedia.org/wiki/Fugitive_Slave_Act_of_1850