In his 1991 book Secession: The Morality of Political Divorce From Fort Sumter to Lithuania and Quebec, philosophy professor Allen Buchanan outlined limited rights to secession under certain circumstances, mostly related to oppression by people of other ethnic or racial groups, and especially those previously conquered by other people.
According to the 2007 book Secession and Security by George Mason political scientist Ahsan Butt, states respond violently to secessionist movements if the potential state would pose a greater threat than a violent secessionist movement would. States perceive future war as likely with a potentially new state if the ethnic group driving the secessionist struggle has deep identity division with the central state, and if the regional neighborhood is violent and unstable.
Some theories of secession emphasize a general right of secession for any reason ("Choice Theory") while others emphasize that secession should be considered only to rectify grave injustices ("Just Cause Theory"). Some theories do both. A list of justifications may be presented supporting the right to secede, as described by Allen Buchanan, Robert McGee, Anthony Birch, Jane Jacobs, Frances Kendall and Leon Louw, Leopold Kohr, Kirkpatrick Sale, and various authors in David Gordon's "Secession, State and Liberty", includes:
Aleksander Pavkovic, associate professor at the Department of Politics and International Studies at Macquarie University in Australia and the author of several books on secession describes five justifications for a general right of secession within liberal political theory:
Allen Buchanan, who supports secession under limited circumstances, lists arguments that might be used against secession:
According to University of California, Santa Barbara, political scientist Bridget L. Coggins, there are four potential explanations in the academic literature for the drastic increase in state birth during the 20th century: