A partisan realignment (often just realignment) is a durable shift in a political system's configuration of voters' partisan identifications and political parties' vote shares. Some realignments occur fairly suddenly as a result of a single critical election, while other, secular realignments occur gradually over the course of several election cycles.
Within political science, the concept of partisan realignment stems from two articles published by V.O. Key, Jr. in the Journal of Politics during the 1950s: "A Theory of Critical Elections" (1955) and "Secular Realignment and the Party System" (1959).
Realignment in American politics
The realignment framework has been applied most extensively to the political development of the United States. In fact, while Key's initial identification of the "critical election" category was aimed at understanding democratic political systems in general, his own analysis focused exclusively on American elections.
Controversy and criticism
In recent decades, the realignment framework and its relevance to American politics has been a subject of considerable controversy among political scientists.