The first—and perhaps the most important—political rivalry in U.S. history was between Alexander Hamilton and Thomas Jefferson. The two Founding Fathers clashed over political differences, each trying to sway President George Washington to his side. But there’s more to the Hamilton and Jefferson feud than you thought. Why did Thomas Jefferson hate Alexander Hamilton? He called Hamilton a corrupt monarchist, a traitor to the country—and their beef went far beyond political differences. In the rivalry between Jefferson and Hamilton, both men would destroy their own reputations in order to attack each other.