The correct answer is: It was done without clear constitutional authority.
The Louisiana Purchase in 1803 involved acquiring a vast territory from France, and this raised questions about the constitutional authority of the federal government to make such a purchase, as the Constitution did not explicitly grant the federal government the power to acquire new land. President Thomas Jefferson, despite being a proponent of limited government, justified the purchase as advantageous for the nation, thus expanding governmental power beyond what was explicitly outlined in the Constitution.