This clearly repudiated the Supreme Court’s notorious 1857 Dred Scott decision, in which Chief Justice Roger Taney wrote that a Black man, even if born free, could not claim rights of citizenship under the federal constitution.
The growth of Sub-Saharan African Kingdoms was assisted by Agriculture and Trade. Increase in trade routes led to increase in transportation that played a major in increasing the trade activities that led to flourishing of these kingdoms, the major exports included slaves, gold, copper and animal products such as ivory, pelts, feathers and tortoise shells.
To combat the Kansas-Nebraska act and the expansion of slavery to American territories.
The answer is that it has allowed cultures to spread quickly and easily from one country to another.