In the early years of the new republic, the first political parties formed over the interpretations of the Constitution. Alexander Hamilton, the de facto leader of the Federalists, and Thomas Jefferson, leader of the Democratic-Republicans butted heads in one of the first political battles in American history. After Hamilton proposed a national bank, Jefferson argued that because the Constitution did not explicitly give the federal government the power to set up a bank, this power was then reserved for the states. Ready, set, face off!