A coup d'état ( /ˌkuː deɪˈtɑː/ ; French: [ku.de.ta] ), also known simply as a coup ( /kuː/ ), a putsch ( /pʊtʃ/ ), golpe de estado , or an overthrow , is the illegal and overt seizure of a state by the military or other elites within the state apparatus. 
The phrase coup d'état ( French pronunciation: [ku deta] ) is French, literally meaning a "stroke of state" or "blow against the state". In French the word " État " ( French: [e.ta] ), denoting a sovereign political entity, is capitalized. 
Although the concept of a coup d'état has featured in politics since antiquity, the phrase is of relatively recent coinage; the Oxford English Dictionary identifies it as a French expression meaning a "stroke of state". The phrase did not appear within an English text before the 19th century except when used in translation of a French source, there being no simple phrase in English to convey the contextualized idea of a "knockout blow to the existing administration within a state".
One early use within text translated from French was in 1785 in a printed translation of a letter from a French merchant, commenting on an arbitrary decree or " arrêt " issued by the French king restricting the import of British wool. What may be its first published use within a text composed in English is an editor's note in the London Morning Chronicle , 7 January 1802, reporting the arrest by Napoleon in France, of Moreau , Berthier , Masséna , and Bernadotte :
There was a report in circulation yesterday of a sort of coup d'état having taken place in France, in consequence of some formidable conspiracy against the existing government.
...the actors in torture, the distributors of the poisoning draughts, and the secret executioners of those unfortunate individuals or families, whom Bonaparte's measures of safety require to remove. In what revolutionary tyrants call grand [s] coups d'état , as butchering, or poisoning, or drowning, en masse , they are exclusively employed.
Use of the phrase
Clayton Thyne and Jonathan Powell's dataset of coups defines attempted coups as "illegal and overt attempts by the military or other elites within the state apparatus to unseat the sitting executive."  They arrive at this definition by combining common definitions in the existing literature and removing specificities and ambiguities that exist in many definitions. 
In looser usage, as in "intelligence coup" or "boardroom coup", the term simply refers to gaining a sudden advantage on a rival.
Since an unsuccessful coup d'état in 1920 (the Kapp Putsch ), the Swiss-German word Putsch (pronounced [pʊtʃ] , coined for the Züriputsch of 6 September 1839, in Zurich ), also denotes the politico-military actions of an unsuccessful minority reactionary coup.  
Other recent and notable unsuccessful minority reactionary coups that are often referred to as Putsches are the 1923 Beer Hall Putsch and Küstrin Putsch , 1961 Algiers Putsch and the 1991 August Putsch . Putsch was used as disinformation by Hitler and his Nazi supporters to falsely claim that he had to suppress a reactionary coup during the Night of the Long Knives . Germans still use the term Röhm-Putsch to describe the murders, the term given to it by the Nazi regime, despite its unproven implication that the murders were necessary to prevent a coup. Thus, German authors often use quotation marks or write about the sogenannter Röhm-Putsch ("so-called Röhm Putsch") for emphasis. 
Pronunciamiento ("pronouncement") is a term of Spanish and Latin-American origin for a special type of coup d'état . The coup d'état (called golpe de estado in Spanish ) was more common in Spain and South America, while the pronunciamiento was more common in Central America and Mexico . The pronunciamiento is the formal explanation for deposing the regnant government, justifying the installation of the new government that was effected with the golpe de estado . A "barracks revolt" or cuartelazo is also a term for military revolt, from the Spanish term cuartel ("quarter" or "barracks"). Specific military garrisons are the sparking factor for a larger military revolt against the government.
One author makes a distinction between a coup and a pronunciamiento . In a coup, it is the military, paramilitary, or opposing political faction that deposes the current government and assumes power; whereas, in the pronunciamiento , the military deposes the existing government and installs an (ostensibly) civilian government.
According to Clayton Thyne and Jonathan Powell's coup dataset, there were 457 coup attempts from 1950 to 2010, of which 227 (49.7%) were successful and 230 (50.3%) were unsuccessful.  They find that coups have "been most common in Africa and the Americas (36.5% and 31.9%, respectively). Asia and the Middle East have experienced 13.1% and 15.8% of total global coups, respectively. Europe has experienced by far the fewest number of coup attempts: 2.6%."  Most coup attempts occurred in the mid-1960s, but there were also large numbers of coup attempts in the mid-1970s and the early 1990s.  Successful coups have decreased over time.  Coups that occur in the post-Cold War period are more likely to result in democratic systems.    Coups that occur during civil wars shorten the war's duration.  Research suggests that protests spur coups, as they help elites within the state apparatus to coordinate coups. 
A 2016 study categorizes coups into four possible outcomes: 
- Failed coup
- No regime change, such as when a leader is illegally shuffled out of power without changing the identity of the group in power or the rules for governing
- Replacement of incumbent dictatorship with another
- Ouster of the dictatorship followed by democratization (also called "democratic coups") 
The 2016 study found that about half of all coups — both during and after the Cold War — install new autocratic regimes.  New dictatorships launched by coups engage in higher levels of repression in the year that follows the coup than existed in the year leading to the coup.  One third of coups during the Cold War and 10 percent of post-Cold War coups reshuffled the regime leadership.  Democracies were installed in the wake of 12 percent of Cold War coups and 40 percent of the post-Cold War coups. 
A 2003 review of the academic literature found that the following factors were associated with coups:
- officers' personal grievances
- military organizational grievances
- military popularity
- military attitudinal cohesiveness
- economic decline
- domestic political crisis
- contagion from other regional coups
- external threat
- participation in war
- and military's national security doctrine
- officers' political culture
- noninclusive institutions
- colonial legacy
- economic development
- undiversified exports
- officers' class composition
- military size
- strength of civil society
- regime legitimacy and past coups. 
The literature review in a 2016 study includes mentions of ethnic factionalism, supportive foreign governments, leader inexperience, slow growth, commodity price shocks, and poverty. 
The cumulative number of coups is a strong predictor of future coups.    Hybrid regimes are more vulnerable to coups than very authoritarian states or democratic states.  A 2015 study finds that terrorism is strongly associated with re-shuffling coups.  A 2016 study finds that there is an ethnic component to coups: "When leaders attempt to build ethnic armies, or dismantle those created by their predecessors, they provoke violent resistance from military officers."  Another 2016 study shows that protests increase the risk of coups, presumably because they ease coordination obstacles among coup plotters and make international actors less likely to punish coup leaders.  A third 2016 study finds that coups become more likely in the wake of elections in autocracies when the results reveal electoral weakness for the incumbent autocrat.  A fourth 2016 study finds that inequality between social classes increase the likelihood of coups.  A fifth 2016 study rejects the notion that participation in war makes coups more likely; to the contrary, coup risk declines in the presence of enduring interstate conflict.  A sixth 2016 study finds no evidence that coups are contagious; one coup in a region does not make other coups in the region likely to follow.  One study found that coups are more likely to occur in states with small populations, as there are smaller coordination problems for coup-plotters. 
A 2017 study found that autocratic leaders whose states were involved international rivalries over disputed territory were more likely to be overthrown in a coup. The authors of the study provide the following logic for why this is: "Autocratic incumbents invested in spatial rivalries need to strengthen the military in order to compete with a foreign adversary. The imperative of developing a strong army puts dictators in a paradoxical situation: to compete with a rival state, they must empower the very agency—the military—that is most likely to threaten their own survival in office." 
In what is referred to as "coup-proofing", regimes create structures that make it hard for any small group to seize power. These coup-proofing strategies may include the strategic placing of family, ethnic, and religious groups in the military; creation of an armed force parallel to the regular military, and development of multiple internal security agencies with overlapping jurisdiction that constantly monitor one another.  Research shows that some coup-proofing strategies reduce the risk of coups occurring.   However, coup-proofing reduces military effectiveness,   and limits the rents that an incumbent can extract. 
A 2016 study shows that the implementation of succession rules reduce coup attempts.  Succession rules are believed to hamper coordination efforts among coup plotters by assuaging the elites who have more to gain with patience than with plotting. 
According to political scientists Curtis Bell and Jonathan Powell, coup attempts in neighbouring countries lead to greater coup-proofing and coup-related repression in a region.  A 2017 study finds that countries’ coup-proofing strategies are heavily influenced by other countries with similar histories. 
Research suggests that coups promoting democratization in staunchly authoritarian regimes, have become less likely to end democracy over time, and that the positive influence has strengthened since the end of the Cold War.    
A 2014 study found that "coups promote democratization, particularly among states that are least likely to democratize otherwise".  The authors argue that coup attempts can have this consequence because leaders of successful coups have incentives to democratize quickly in order to establish political legitimacy and economic growth while leaders who stay in power after failed coup attempts see it as a sign that they must enact meaningful reforms to remain in power.  A 2014 study found that 40% of post-Cold War coups were successful. The authors argue that this may be due to the incentives created by international pressure.  A 2016 study found that democracies were installed in 12 percent of Cold War coups and 40 percent of the post-Cold War coups. 
Repression after failed coups, and counter-coups
According to Naunihal Singh, author of Seizing Power: The Strategic Logic of Military Coups (2014), it is "fairly rare" for the prevailing existing government to violently purge the army after a coup has been foiled. If it starts mass killing elements of the army, including officers who were not involved in the coup, this may trigger a "counter-coup" by soldiers who are afraid they will be next. To prevent such a desperate counter-coup that may be more successful than the initial attempt, governments usually resort to firing prominent officers and replacing them with loyalists instead.
Some research suggests that increased repression and violence typically follow coup attempts (whether they're successes or failures).  However, some tentative analysis by political scientist Jay Ulfelder finds no clear pattern of deterioration in human-rights practices in wake of failed coups in post-Cold War era. 
A 2017 study finds that the use of state broadcasting by the putschist regime after Mali’s 2012 coup did not elevate explicit approval for the regime. 
The international community tends to react adversely to coups by reducing aid and imposing sanctions. A 2015 study finds that "coups against democracies, coups after the Cold War, and coups in states heavily integrated into the international community are all more likely to elicit global reaction."  Another 2015 study shows that coups are the strongest predictor for the imposition of democratic sanctions.  A third 2015 study finds that Western states react strongest against coups of possible democratic and human rights abuses.  A 2016 study shows that the international donor community in the post-Cold War period penalizes coups by reducing foreign aid .  The US has been inconsistent in applying aid sanctions against coups both during the Cold War and post-Cold War periods, a likely consequence of its geopolitical interests. 
Organizations such as the African Union and Organization of American States have adopted anti-coup frameworks. Through the threat of sanctions, the organizations actively try to curb coups. A 2016 study finds that the African Union has played a meaningful role in reducing African coups.
A forthcoming study in the Journal of Conflict Resolution finds that negative international responses to regimes created in coups have a significant influence on the sustainability of those regimes.  The study finds that "state reactions have the strongest effect during the Cold War, while international organizations matter the most afterward."  Negative international responses from strong actors matter the most. 
Current leaders who assumed power via coups d'état
1 Monarch who overthrew his father in a bloodless palace coup.
2 Subsequently, confirmed by a narrow margin in the 2009 Mauritanian presidential election , which was deemed "satisfactory" by international observers.
3 de facto Prime Minister at that time, but under court order to resign
4 Hadi resigned on 22 January 2015.
5 Mugabe resigned on 21 November 2017.
- Civil-military relations
- Contrast with civilian control of the military
- Coup d'État: A Practical Handbook
- Coup de main
- Leadership spill
- List of fictional revolutions and coups
- List of protective service agencies
- Military dictatorship
- Political corruption
- Political warfare
- Seven Days in May
- Soft coup
- State collapse