The issue of runaway slaves was important to most southerners because

a. the south was losing a significant and irreplaceable portion of its labor force. the overwhelming success of the underground railroad posed critical and immediate threat to the southern way of life.
b. while the overall loss of property was relatively insignificant, the loss of honor and the passing of moral judgments by northerners were felt more.
c. escaped slaves would likely organize a black army to stage armed rebellions against white southern planters and their plantations.
d. escaped slaves would travel north or to canada and quickly undermine the legitimacy of southerners' racial superiority theories among political leaders of the north and the south.