In what way was the decision to buy Louisiana a difficult one for President Jefferson to make?
The Constitution did not directly address whether such a purchase was even legal.
Jefferson faced opposition from the Federalist party over whether acquiring new land was even legal, as the Constitution did not explicitly allow it. Jefferson cited the presidential power to make treaties as ample justification. Jefferson had sought only the city of New Orleans initially, for one million 1803 US dollars, but Napoleon's difficulties holding on to Haiti inspired him to cut his losses on North America and he offered Jefferson the entire Louisiana Territory for $15 million.
The western boundaries of the new territory were not very clearly defined. Jefferson had hoped to create an American port on the Pacific, and the Louisiana Purchase gave him a nebulous claim to modern-day Idaho, Washington and Oregon--lands also claimed by Britain, Spain and Russia. Acquiring clear title to the Oregon Territory would take another 45 years.