In attempting to understand more fully the U.S. Supreme Court’s impact on national policymaking, scholars have examined Supreme Court policymaking as part of the “relatively cohesive alliances that endure for long periods of time” (Dahl, 1957: 280). These alliances or “party systems” represent relatively distinctive patterns in the general shape of national policy (Chambers and Burnham, 1975). It is common for historians to characterize the Jacksonian party system of 1828-1860 as a period in American history when national policy was aimed at aiding agrarian interests, or the First and Second Republican party systems in the later part of the nineteenth century as periods when national policy favored the rising industrial and financial interests. The change from one party system to another is the result of a process political scientists and historians have termed “partisan realignment” (Key, 1955). Periods of realignment in American politics are marked by a rapid change in the social and political agenda, which results in a significant and durable change in the party support in the electorate as well as in a significant change in institutional roles and national policy (Burnham, 1970; Jahnige, 1971; Sundquist, 1973; Trilling and Campbell, 1980). The new party balance may give rise to a shift from the dominance of one party to another, or an entirely new party system may develop. A relationship between mass electoral behavior and public policy appears to exist during periods of partisan realignment. The elections that produce this change in the party systems are termed “critical elections.”