Answer:
Jefferson's most fundamental political belief was an "absolute acquiescence in the decisions of the majority." Stemming from his deep optimism in human reason, Jefferson believed that the will of the people, expressed through elections, provided the most appropriate guidance for directing the republic's course.
Some more explanation on why American important to him:
Thomas Jefferson was the primary draftsman of the U.S. Declaration of Independence, the nation's first secretary of state and the second vice president under John Adams. He was responsible for doubling the size of the United States by successfully brokering the Louisiana Purchase.