Final answer:
The Federalist Party was the political party concerned that Thomas Jefferson might initiate a violent second revolution in the U.S.A. due to their fear of unchecked democracy and the events of the French Revolution.
Step-by-step explanation:
The political party that was afraid that Thomas Jefferson might lead a bloody second Revolution in the U.S.A. was the Federalist Party. During this time, the U.S. witnessed the formation of the Federalists and the Democratic-Republicans. The Federalists were known for their belief in a strong federal government and skepticism of too much democracy, fearing that could lead to an anarchy similar to what they perceived in the French Revolution. The Democratic-Republican Party, on the other hand, favored states' rights, limited federal power, and looked upon Thomas Jefferson as a hero of these principles. Consequently, it was the Federalists who were concerned that Jefferson's leadership might bring about radical changes akin to a revolution.