Political parties in the United States are mostly dominated by a two-party system. However, the United States Constitution has always been silent on the issue of political parties; at the time it was signed in 1787, there were no parties in the nation. Indeed, no nation in the world had voter-based political parties. The need to win popular support in a republic led to the American invention of voter-based political parties in the 1790s. Americans were especially innovative in devising new campaign techniques that linked public opinion with public policy through the party.
Political scientists and historians have divided the development of America's two-party system into five eras. The first two-party system consisted of the Federalist Party, who supported the ratification of the Constitution, and the Democratic-Republican Party or the Anti-Federalists, who opposed the powerful central government, among others, that the Constitution established when it took effect in 1789. The modern two-party system consists of the Democratic Party and the Republican Party. Several third parties also operate in the U.S., and from time to time elect someone to local office. The largest third party since the 1980s is the Libertarian Party.
The United States Constitution has never formally addressed the issue of political parties. The Founding Fathers did not originally intend for American politics to be partisan. In Federalist Papers No. 9 and No. 10, Alexander Hamilton and James Madison, respectively, wrote specifically about the dangers of domestic political factions. In addition, the first President of the United States, George Washington, was not a member of any political party at the time of his election or throughout his tenure as president. Furthermore, he hoped that political parties would not be formed, fearing conflict and stagnation, as outlined in his Farewell Address. Nevertheless, the beginnings of the American two-party system emerged from his immediate circle of advisers. Hamilton and Madison, who wrote the aforementioned Federalist Papers against political factions, ended up being the core leaders in this emerging party system. It was the split camps of Federalists, given rise with Hamilton as a leader, and Democratic-Republicans, with Madison and Thomas Jefferson at the helm of this political faction, that created the environment in which partisanship, once distasteful, came to being.