Final answer:
The term 'Bleeding Kansas' refers to the violent conflicts in Kansas between proslavery and antislavery factions, influenced by figures like John Brown, and exacerbated by fraudulent voting and extreme legislation.
Step-by-step explanation:
The nickname given to the series of violent confrontations in the state of Kansas between proslavery and antislavery factions was Bleeding Kansas. These events were a direct consequence of the Kansas-Nebraska Act and the application of popular sovereignty to the issue of slavery in these territories. John Brown's involvement in Kansas, particularly his actions during the Pottawatomie Massacre, was part of the larger conflict that propagated the nickname Bleeding Kansas as the territory became emblematic of the sectional strife tearing the nation apart. The proslavery legislature, backed by fraudulent activities from proslavery advocates often called border ruffians, and dramatic events like the Sack of Lawrence and Brown's own violent responses, escalated the tensions to the level that the crisis became a national issue.