Answer:
Before the fugitive slave act, slaves in the South could (not very easily) possibly make it to the Northern states where slavery was outlawed, and live the rest of their lives as free people. But, the fugitive slave act (passed in 1850) required that even if slaves were able to escape to the North, they were still slaves, and had to be sent back to their owners in the South. It put the responsibility on the federal government to find and return slaves. So the act further engrained slavery into America's laws, which was a turning point leading to the Civil War, and made Northern abilitionists very angry, as it was extending the practice of slavery rather than trying to bring it to an end. Hope this helps.