Final answer:
The violence between proslavery and anti-slavery forces in the Kansas Territory was labeled Bleeding Kansas, reflecting the intense conflict over slavery's legality in the new state.
Step-by-step explanation:
In the eastern newspapers, the violence between proslavery and anti-slavery forces was labeled Bleeding Kansas. The term refers to the series of violent civil conflicts in the Kansas Territory between 1854 and 1859, which emerged from the debate over the legality of slavery in the proposed state. Proslavery and antislavery advocates engaged in intense conflict, notably in events such as the Sack of Lawrence and the Pottawatomie Massacre. This violence was a manifestation of the deep national division over slavery, further inflamed by the Kansas-Nebraska Act and the abolitionist's growing militancy, as demonstrated by individuals like John Brown.