Why was Jefferson unsure about the Louisiana purchase-?

Answer 1

He had doubts about the constitutionality of the purchase. Any power not specifically granted to the federal government by the U.S. Constitution belongs to the states or to the people. The Constitution makes no mention regarding the acquiring of new land. It was eventually reasoned that since the power to make treaties was specifically granted to the President, and since the only way to acquire new land, aside from seizing it, is by treaty, then acquiring land by treaty would be unconstitutional only if the Constitution specifically denied the President that power (it does not).

Answer 2

Jefferson was unsure about the Louisiana Purchase because the Constitution did not have a section about purchasing land. He wasn't positive it was a legal move.

Answer 3

Because he was buying it from Napoleon