<Li> The Nashville Convention of nine Southern states discusses states' rights and slavery in June; in November, the convention talks about secession but adjourns due to the passage of the laws that constitute the Compromise of 1850 . </Li> <Li> Utah is organized as a territory and adopts a slave code . Only 29 slaves are found in the territory in 1860 . </Li> <Li> In October, the Boston Vigilance Committee frees two fugitive slaves, Ellen and William Craft, from jail and being returned to Georgia . </Li> <Tr> <Td> 1851 </Td> <Td> <Ul> <Li> Southern Unionists in several states defeat secession measures . Mississippi's convention denies the existence of the right to secession . </Li> <Li> In February, a crowd of black men in Boston frees fugitive slave Shadrach Minkins, also known as Fred Wilkins, who was being held in the federal courthouse, and help him escape to Canada . </Li> <Li> In April, the government guards fugitive slave Thomas Sims with 300 soldiers to prevent local sympathizers from helping him with an escape attempt . </Li> <Li> In September 1851, free blacks confront a slave owner, his son and their allies who are trying to capture two fugitive slaves at Christiana, Pennsylvania . In the gunfight that followed, three blacks and the slave owner are killed while his son is seriously wounded . </Li> <Li> In October 1851, black and white abolitionists free fugitive slave Jerry McHenry from the Syracuse, New York jail and allow his escape to Canada . </Li> </Ul> </Td> </Tr>

What are the three most important developments leading up to the american civil war