Secession is the withdrawal of a group from a larger entity, especially a political entity, but also from any organization, union or military alliance. Some of the most famous and significant secessions have been: the Southern States seceding from the Union - which is one of the causes for the American Civil War, the former Soviet republics leaving the Soviet Union after its dissolution, Texas leaving Mexico during the Texas Revolution, Biafra leaving Nigeria and returning after losing the Nigerian Civil War, and Ireland leaving the United Kingdom. Threats of secession can be a strategy for achieving more limited goals. It is, therefore, a process, which commences once a group proclaims the act of secession (for example declaration of independence). A secession attempt might be violent or peaceful, but the goal is the creation of a new state or entity independent from the group or territory it seceded from.
Secession theory.
There is no consensus regarding the definition of political secession, and a lot of new political theory on the subject. The political philosophers of the rights and moral justification for secession began to develop as recently as the 1980s.American philosopher Allen Buchanan offered the first systematic account of the subject in the 1990s and contributed to the normative classification of the literature on secession. In his 1991 book Secession: The Morality of Political Divorce From Fort Sumter to Lithuania and Quebec, 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. In his collection of essays from secession scholars, Secession, State, and Liberty, professor David Gordon challenges Buchanan, making a case that the moral status of the seceding state is unrelated to the issue of secession itself.
According to the 2017 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.