1. Complete change from one constitution to another
2. Modification of an existing constitution.

Revolutions have occurred throughout human history and vary widely in terms of methods, duration, and motivating ideology. Their results include major changes in culture, economy, and socio-political institutions.

Scholarly debates about what does and does not constitute a revolution center around several issues. Early studies of revolutions primarily analyzed events in European history from a psychological perspective, but more modern examinations include global events and incorporate perspectives from several social sciences, including sociology and political science. Several generations of scholarly thought on revolutions have generated many competing theories and contributed much to the current understanding of this complex phenomenon.

Political and socioeconomic revolutions

Perhaps most often, the word 'revolution' is employed to denote a change in socio-political institutions.Jack Goldstone, "Theories of Revolutions: The Third Generation, World Politics 32, 1980:425-53John Foran, "Theories of Revolution Revisited: Toward a Fourth Generation", Sociological Theory 11, 1993:1-20Clifton B. Kroeber, Theory and History of Revolution'', Journal of World History 7.1, 1996: 21-40 Jeff Goodwin gives two definitions of a revolution. A broad one, where revolution is "any and all instances in which a state or a political regime is overthrown and thereby transformed by a popular movement in an irregular, extraconstitutional and/or violent fashion"; and a narrow one, in which "revolutions entail not only mass mobilization and regime change, but also more or less rapid and fundamental social, economic and/or cultural change, during or soon after the struggle for state power."Goodwin, p.9. Jack Goldstone defines them as

an effort to transform the political institutions and the justifications for political authority in society, accompanied by formal or informal mass mobilization and noninstitutionalized actions that undermine authorities.Jack Goldstone, "Towards a Fourth Generation of Revolutionary Theory", Annual Review of Political Science 4, 2001:139-87

Political and socioeconomic revolutions have been studied in many social sciences, particularly sociology, political sciences and history. Among the leading scholars in that area have been or are Crane Brinton, Charles Brockett, Farideh Farhi, John Foran, John Mason Hart, Samuel Huntington, Jack Goldstone, Jeff Goodwin, Ted Roberts Gurr, Fred Halliday, Chalmers Johnson, Tim McDaniel, Barrington Moore, Jeffery Paige, Vilfredo Pareto, Terence Ranger, Eugen Rosenstock-Huessy, Theda Skocpol, James Scott, Eric Selbin, Charles Tilly, Ellen Kay Trimbringer, Carlos Vistas, John Walton, Timothy Wickham-Crowley and Eric Wolf.Jeff Goodwin, No Other Way Out: States and Revolutionary Movements, 1945-1991. Cambridge University Press, 2001, p.5