Led up to civil war
The Louisiana Purchase was a big lead up to the Civil War in many ways. One way was that Thomas Jefferson purchased the Louisiana Province without Congress's approval. Some citizens such as the New England Federalists thought this was unfair because the purchase greatly reduced their political power in the Government. This caused much division between the colonists. Another issue that led up to the Civil War caused by the Louisiana Purchase was slavery. More land in the West meant the decision if Slavery should expand westward or not. The South wanted slavery in the west because its what they depended on. While the North didn't want slavery expanding West and was afraid that they would be over ruled if slavery took over the South. This caused much sectional tension and was a major event that led up to the Civil War.
Manifest Destiny
The connection between the Louisiana Purchase and the Manifest Destiny is quite simple. Their would of been no Manifest Destiny without the Louisiana Purchase. After the Louisiana Purchase America had extended all the way to the Rocky Mountains. Americans believed that the United States would stretch from the Pacific Ocean to the Atlantic Ocean. They wanted the Americas to go coast to coast. The land West in the Louisiana province provided hope of change for many people. It offered a new start, and a chance to make money. This was also part of the Manifest Destiny. But the Manifest Destiny only existed because the Louisiana Purchase offered all that land in the West. Without the Louisiana Purchase the United States would of never expanded coast to coast and most likely America would have slowly died.