Final answer:
The Kansas-Nebraska Act of 1854 implemented popular sovereignty to determine the legal status of slavery in the Kansas and Nebraska territories, leading to violent conflicts known as 'Bleeding Kansas'. This period included guerrilla warfare and significant political unrest, illustrating the failures of popular sovereignty to resolve the divisive issue of slavery.
Step-by-step explanation:
The Act that used the concept of popular sovereignty to decide the slavery issue in Kansas and Nebraska was the Kansas-Nebraska Act of 1854. This principle allowed the settlers of a territory to decide whether to allow slavery, a contentious issue following the acquisition of new territories after the Mexican-American War. The application of popular sovereignty in these territories, as intended by the Kansas-Nebraska Act, led to violent confrontations known as 'Bleeding Kansas'. This period was characterized by a series of violent political confrontations between anti-slavery Free Staters and pro-slavery "Border Ruffian" elements that took place in the Kansas Territory. The tensions escalated into guerilla warfare and had significant implications for the political landscape of the United States, contributing to the rise of the Republican Party and sectional conflict between the North and South.
The culmination of these tensions during the period of Bleeding Kansas failed to provide a peaceful solution to the dispute over slavery in the territories. Instead, the intense violence demonstrated the limitations of popular sovereignty as a means to resolve deeply rooted ideological disagreements, foreshadowing the Civil War. The battle for Kansas also featured notable episodes such as the Sack of Lawrence by pro-slavery forces and the retaliatory Pottawatomie Massacre by abolitionist John Brown and his followers, further inflaming the divide between anti-slavery and pro-slavery Americans.