Authoritarianism is a form of government characterized by strong central power and limited political freedoms. Under an authoritarian regime, individual freedoms are subordinate to the state, and there is no constitutional accountability. Authoritarian regimes can be autocratic, with power concentrated in one person, or can be a committee, with power shared among officials and government institutions. The political scientist Juan Linz defined authoritarianism in an influential 1964 work as possessing four qualities: Linz distinguished new forms of authoritarianism from personalistic dictatorships and totalitarian states, taking Francoist Spain as an example. Unlike personalistic dictatorships, new forms of authoritarianism have institutionalized representation of a variety of actors (in Spain's case, including the military, the Catholic Church, Falange, monarchists, technocrats and others). Unlike totalitarian states, the regime relies on passive mass acceptance rather than popular support. Some scholars also mention the emergence of a different type of regime - the hybrid regime - in the post-Cold War era. Several subtypes of authoritarian regimes have been identified by Linz and others. Linz identified the two most basic subtypes as traditional authoritarian regimes and bureaucratic-military authoritarian regimes: Subtypes of authoritarian regime identified by Linz are: corporatist or organic-statistic, racial and ethnic 'democracy' and post-totalitarian. Another type of authoritarian regime is the 'competitive authoritarian' regime, a 'civilian regimes in which formal democratic institutions exist and are widely viewed as the primary means of gaining power, but in which incumbents' abuse of the state places them at a significant advantage vis-à-vis their opponents.' The term was coined by Steven Levitsky and Lucan A. Way in their 2010 book of the same name to discuss a type of hybrid regime that emerged during and after the Cold War. Competitive authoritarian regimes differ from fully authoritarian regimes in that elections are regularly held, the opposition can openly operate without a high risk of exile or imprisonment, and 'democratic procedures are sufficiently meaningful for opposition groups to take them seriously as arenas through which to contest for power.' However, competitive authoritarian regimes lack one or more of the three characteristics of democracies: free elections (i.e., elections untainted by substantial fraud or voter intimidation); protection of civil liberties (i.e., the freedom of speech, press, and association), and an even playing field (in terms of access to resources, the media, and legal recourse). Authoritarian regimes are also sometimes subcategorized by whether they are personalistic or populist. Personalistic authoritarian regimes are characterized by arbitrary rule and authority exercised 'mainly through patronage networks and coercion rather than through institutions and formal rules'. Personalistic authoritarian regimes have been seen in post-colonial Africa. By contrast, populist authoritarian regimes 'are mobilizational regimes in which a strong, charismatic, manipulative leader rules through a coalition involving key lower-class groups'. Examples include Argentina under Perón, Egypt under Nasser and Venezuela under Chávez and Maduro. Authoritarianism is characterized by highly concentrated and centralized power maintained by political repression and the exclusion of potential challengers. It uses political parties and mass organizations to mobilize people around the goals of the regime. Adam Przeworski has theorized that 'authoritarian equilibrium rests mainly on lies, fear and economic prosperity'. Authoritarianism also tends to embrace the informal and unregulated exercise of political power, a leadership that is 'self-appointed and even if elected cannot be displaced by citizens' free choice among competitors', the arbitrary deprivation of civil liberties and little tolerance for meaningful opposition.