Party realignment refers to a significant and lasting shift in the political landscape, where the support base of major political parties changes dramatically. This can occur due to various factors, such as economic crises, social movements, or demographic changes, leading to new coalitions and altering the balance of power. Historically, party realignment has been marked by critical elections, such as the New Deal era in the 1930s, when the Democratic Party gained support from various groups, including labor unions and minorities, while the Republican Party lost ground. These shifts can reshape party ideologies and influence future political dynamics.