Fugitive slave incidents, long predating the Fugitive Slave Act of 1850, raised for North and South alike troubling issues. For Southerners, escaping slaves both provided active satire on their idealized claims about slavery and suggested most directly their frightening dependence on others without commitment to their system. For the North, these escapees most movingly put the peculiar institution in human terms, while mocking the favorite conservative pretense that the North had nothing to do with slavery. And when that pretense was punctured, Northern indifference to slavery deflated.
For abolitionists, fugitives had additional meaning. Taunted that all they did was talk, abolitionists found in fugitives a chance to act in ways that showed they cared enough to endanger self in aid of slaves. Here was the spice of both personal danger and meaningful action, while for everyone, fugitives offered proof that slaves were fully human, men and women willing to take greater risk for freedom than had white Americans for generations. When Northerners saw blacks who risked all to be free, sometimes blacks who long had proved, despite racist constrictions, their ability to care well for themselves and their families, arrested on Northern soil by Northern officers, it became impossible to pretend that slavery was only the South’s business, and difficult for most to avoid feeling a stab of respect or kinship for someone being chained for life while a liberty-loving, or a least -talking, people looked on. Abolitionists noticed how many of those normally hostile to them shared their sentiments on such occasions.