Final answer:
President Jefferson's action that did NOT reflect his belief was sending vessels to fight Barbary pirates.
Step-by-step explanation:
President Jefferson's action that did NOT reflect his belief that the U.S. should avoid foreign entanglements and maintain a small military force was the sent vessels to fight Barbary pirates. This action contradicted his stated beliefs because it involved the use of military force in a foreign conflict.
Learn more about President Jefferson's actions