Political scientists and historians who study American politics have discerned between the 1790s and the 1960s five long-term periods of stability in voting behavior, including both voters' choices among parties and turnout, and in many federal policies. Each stable period has lasted about thirty-five years, and each was initiated and ended by a short-term period of change. These longterm periods of stability have been termed “party systems” or “electoral systems.” The short-term periods of change have been called “critical elections” or “critical realignments.” Though this analytical construct has attracted some criticism, it has proven quite durable as a way to understand large patterns in American political history.
This interpretive framework for American political history designates the years 1860–1896 as the third party system and 1890–1896 as a period of critical realignment. Even those who reject the party systems and critical realignments analysis usually agree that the 1890s were a time of important and far-reaching political change, marking the end of one pattern of politics and the emergence of one different in many ways.