Question

Why was the Louisiana Purchase a bit of an embarrassment for Jefferson

Answer 1

His decision to buy the land went against his own belief to strictly follow the words of the Constitution. 

The Constitution gave no guidance about acquiring lands from other countries. Jefferson was going out on a limb with the Louisiana Purchase.

Answer 2

The Louisiana Purchase wasn't embarrassing to Jefferson. It was a form of "unhinged alters" to America. It went against the masses which is why this could have been seen as a controversial concept to the people back then. Nobody was open to change, therefore in some eyes people thought Jefferson should have been reprimanded.The people thought he was going against the constitution, making it "illegal" for the purchase to even happen.