border ruffians were pro-slavery activists from the slave-state of missouri. from 1854 to 1860 they crossed the state border into kansas territory to force the acceptance of slavery there. the name was applied by free-staters in kansas and abolitionists throughout the north. armed ruffians interfered in territorial elections, and attacked free-state settlements. this violence was the origin of the phrase "bleeding kansas". the ruffians contributed to the growing sectional tensions, and helped bring on the american civil war.