Americans in the South wanted to gain Florida and the people in the North wanted Canada. Jefferson didn’t want to just invade and capture these territories. With the attacks from Natives across the Florida border in the South and the issue of impressment it was hard not to go to war. Jefferson did not want to go to war with Great Britain. A group called the war hawks was born, men who were eager to go to war and get territory. After persuading Jefferson agreed to go to war with Great Britain, and because Spain and Britain were allies they could claim Florida as well. The reason this changed his democracy is he did not want to go to war with European nations, or at all I believe, but he gave in and went to war anyway because of pressure from the war hawks.
Another factor in the changing of Jeffersonian Democracy was the Louisiana Purchase. Robert Livingston and James Monroe were sent to France to discuss a treaty with Napoleon. When they returned they had purchased the Louisiana Territory form Napoleon. Jefferson was both pleased and embarrassed. He was glad to have the territory, but being constitutional as he was, he was not sure it was Constitutional, until his advisors assured him that it fell under his ability to make treaties. This changed his view because it had changed him to be less strict constitutionally and he was already exploring the territory (and beyond) before the treaty was already made.
Jefferson went through a lot of events that changed his view of Democracy and how he ran the nation, but two big ones were the War of 1812, because he went to war even though he personally didn’t want to, and the Louisiana Purchase, because of his belief that the Federal government only had powers expressed in the Constitution.