Final answer:
Jefferson's election was considered a "republican revolution" because it marked the first peaceful transfer of power through a popular election, and a shift in political philosophy from Federalist to Democratic-Republican.
Step-by-step explanation:
Jefferson's election was considered a "republican revolution" because it marked the first time in modern history when a popular election led to a peaceful transfer of power. The election resulted in a shift from the Federalist administrations of Washington and Adams, who favored a strong national government, to Jefferson's Democratic-Republican vision which increased states' rights and limited the power of the federal government. This change in political philosophy was seen as a revolution in the principles of the government, as it represented a departure from the previous governing philosophy.