Final answer:
Opponents thought the Louisiana Purchase unconstitutional because it wasn't explicitly granted by the Constitution, while President Jefferson, despite his strict constitutional views, valued the acquisition for the nation's agrarian expansion and proceeded with the purchase.
Step-by-step explanation:
Opponents of the Louisiana Purchase believed it was unconstitutional because the Constitution did not explicitly grant the President the power to acquire new territory. They were adherents to a strict interpretation of the Constitution and insisted that any powers not expressly provided for in the document were not within the jurisdiction of the federal government. Therefore, acquiring land from a foreign nation was considered an overreach of executive power.
On the other hand, President Thomas Jefferson held a conflicting view despite his usual strict adherence to the Constitution. He valued the agrarian vision for America, seeing the acquisition of farmable land as essential for an agrarian society. Although the constitutional dilemma troubled him, the strategic and economic benefits of controlling New Orleans and access to the Mississippi River outweighed his concerns. These benefits, along with the availability of the land at a bargain price from a motivated seller, Napoleon Bonaparte, led him to proceed with the Louisiana Purchase. Jefferson tasked Robert Livingston and James Monroe with completing the acquisition, which effectively doubled the size of the United States and was viewed as vital for western expansion and agricultural commerce.