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Change in Power and Authority - AP Comparative Government and Politics Study Guide

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Learn with study guides reviewed by top AP teachers. This guide takes about 14 minutes to read.

Getting Started

This chapter explains the critical distinction between a government and a regime, and the different ways that power and authority can change hands within a political system. A government is the set of individuals currently exercising political power, while a regime is the fundamental set of rules and institutions that determine how that power is acquired and used. We will compare how these changes—from routine elections to violent revolutions—occur across the United Kingdom, Russia, China, Mexico, Iran, and Nigeria, revealing the core democratic or authoritarian nature of each state.

What You Should Be Able to Do

  • Explain the difference between a change in government and a change in regime, using examples from at least two course countries.

  • Compare the mechanisms for government change (e.g., elections, appointments) in democratic systems like the UK and Mexico with those in authoritarian systems like China and Iran.

  • Analyze how coups and revolutions in countries like Iran and Nigeria have led to fundamental regime change.

  • Evaluate why democratic regimes can typically maintain sovereignty with less coercive power than authoritarian regimes.

Key Developments & Analysis

The stability and character of a political system are defined by how it handles transitions of power. These transitions can be orderly and institutionalized or abrupt and transformative. The tables below compare these processes across democratic and authoritarian contexts.

Mechanism of ChangeUnited KingdomMexicoWhy This Difference/Similarity Matters
Regular Government ChangeGeneral elections for the House of Commons, held at least every five years. The leader of the majority party becomes prime minister.A presidential election every six years for a single, non-renewable term (sexenio).Both systems have institutionalized, peaceful, and regular electoral processes for changing the head of government, which reinforces the legitimacy of their democratic regimes.
Irregular Government ChangeA successful vote of no confidence in Parliament can force the resignation of the government and trigger new elections.Impeachment is constitutionally possible but has never been successfully used to remove a president.The UK's parliamentary system provides a formal, non-violent mechanism for removing a government between elections, while Mexico's presidential system has more rigid terms of office.
Mechanism of ChangeChinaRussiaWhy This Difference/Similarity Matters
Regular Government ChangeNo national, direct, competitive elections for top leaders. The General Secretary of the Chinese Communist Party (CCP) is selected by party elites.Presidential elections are held, but the system is managed to ensure victory for the incumbent or their chosen successor.Both are authoritarian regimes that control leadership succession. China's process is entirely internal to the party, while Russia uses the facade of elections to legitimize its pre-determined outcomes.
Impact on RegimeGovernment changes (e.g., a new premier) do not challenge the fundamental rules of the single-party regime dominated by the CCP.Government changes occur within the rules of the current constitution, reinforcing the power of the president and the dominant party, thus sustaining the authoritarian regime.In both cases, the process of changing government personnel is designed to prevent, rather than enable, any change to the underlying authoritarian regime.
Mechanism of ChangeIranNigeriaWhy This Difference/Similarity Matters
Sudden/Violent ChangeThe 1979 Islamic Revolution was a sudden, popular uprising that overthrew the monarchy and established a theocratic republic—a fundamental regime change.A history of military coups d'état (e.g., 1966, 1983, 1993) violently overthrew elected governments, leading to repeated and unstable regime changes between democracy and military rule.Both countries have experienced violent transitions. Iran's revolution was a mass movement that created a durable new regime, while Nigeria's coups were elite-driven and created a cycle of regime instability until the 1999 transition to democracy.
Peaceful ChangePresidential elections occur, but candidates are vetted by the Guardian Council, ensuring no fundamental challenge to the theocratic regime.Since 1999, regular and increasingly competitive elections have facilitated peaceful transfers of government power, helping to consolidate the democratic regime of the Fourth Republic.Both systems now use elections, but Iran's are tightly controlled to protect the regime, while Nigeria's, despite challenges, represent a genuine path for peaceful government change within a democratic framework.

Data & Organization Tools

Concept-to-Countries Matrix

Table 1: Regime Change Events

CountryKey EventType of Change
Iran1979 Islamic RevolutionSudden, revolutionary
Mexico2000 Presidential ElectionIncremental, electoral
Nigeria1999 Constitution & ElectionSudden, transitional (from military rule)
Russia1993 Constitutional CrisisSudden, elite-driven

Table 2: Government Change Mechanisms

CountryPrimary MechanismTypical Frequency
United KingdomGeneral Election / Vote of No Confidence≤ 5 years
ChinaCCP Elite Appointment~10 years (historically)
MexicoPresidential Election (Sexenio)6 years
NigeriaPresidential & Legislative Elections4 years

Institution–Actor–Function Map

InstitutionKey ActorsFunction in Power Transitions
UK ParliamentMembers of Parliament (MPs), Prime MinisterCan remove the government via a vote of no confidence; confirms the winner of a general election.
Mexican Federal Electoral Institute (IFE/INE)Independent Commissioners, CitizensOrganizes and oversees elections to ensure fair and peaceful transfers of governmental power.
Iranian Guardian Council12 Jurists (6 appointed by Supreme Leader, 6 by Majlis)Vets all candidates for national office, ensuring that any change in government does not threaten the theocratic regime.
Nigerian MilitaryHigh-ranking military officersHistorically, has overthrown civilian governments through coups d'état, leading to regime change.
Chinese Communist Party (CCP) PolitburoTop 25 party leadersSelects the country's top leadership (government) in a closed, non-electoral process, ensuring regime continuity.

Indicators & Operationalization Mini-Table

ConceptIndicatorOperational Definition (How to measure it)
Change in Political SystemChange in GovernmentThe head of government and/or cabinet members are replaced, but the constitution and the basic rules of the political system remain the same.
Change in RegimeThe fundamental rules and institutions of politics are altered or replaced. This is often marked by the adoption of a new constitution or a dramatic change in the structure of the state (e.g., from monarchy to republic).

Country Anchors Bank

  • Iranian Revolution of 1979: The quintessential example of a rapid and fundamental regime change, where a popular uprising supported by a large portion of the population replaced a monarchy with a theocracy, rewriting the country's political rules.

  • Nigerian Military Coups: A series of violent events (e.g., 1966, 1983) where the military overthrew the elected government, suspended the constitution, and installed a new military regime. This represents a violent and recurring pattern of both government and regime change.

  • Mexico's 2000 Presidential Election: This election marked the end of 71 years of one-party rule by the PRI. It represents a peaceful, incremental regime change accomplished through the ballot box, transitioning Mexico to a competitive multi-party democracy.

  • UK Vote of No Confidence: A key mechanism in a parliamentary system that allows the legislature to remove the executive (the government) without a revolution or coup, demonstrating a peaceful, rule-based process for change.

  • CCP Leadership Succession (China): The opaque process by which top leaders like the General Secretary are chosen by party elites. This is a clear example of a non-electoral, authoritarian method of government change that ensures regime stability.

  • Russia's 2020 Constitutional Amendments: Changes that allowed President Putin to reset his term limits, demonstrating how an authoritarian regime can alter the rules to manage government succession and concentrate power, thereby reinforcing the existing regime.

Skill Snapshots

  • Comparison:

    • A change in government in the UK is determined by competitive popular elections, whereas in China it is determined by the internal decisions of the Communist Party elite.

    • The regime change in Iran (1979) was a violent, sudden revolution, while the regime change in Mexico (c. 2000) was a gradual, peaceful transition achieved through elections.

    • While both Nigeria and the UK hold elections, Nigeria's history of military coups illustrates a vulnerability to violent government and regime change not present in the UK's stable democratic system.

  • Mechanism:

    • Regular elections in Mexico → produce peaceful transfers of power, reinforcing the legitimacy of the democratic regime.

    • A revolution in Iran → led to the complete replacement of the political system's rules and institutions.

    • A coup d'état in Nigeria → violently replaced a civilian government with military rule, causing an abrupt regime change.

  • Change Over Time (Nigeria):

    • Baseline: Post-colonial democracy in the First Republic (1960-1966).

    • Changes: A series of military coups led to decades of authoritarian rule and regime instability. The adoption of the 1999 Constitution marked a formal regime change back to a democratic presidential system.

    • Continuity: The challenge of maintaining stability and preventing violent conflict remains a constant threat to both government and regime, regardless of the formal rules in place.

Common Misconceptions & Clarifications

  • "Regime" and "government" are not synonyms. The government is the group of people in charge (e.g., the Biden administration); the regime is the system of rules (e.g., U.S. constitutional democracy).

  • Regime change is not always violent. Mexico's transition from a one-party dominant state to a multi-party democracy occurred incrementally through the electoral process.

  • Elections do not automatically mean democracy. Authoritarian regimes like Russia and Iran hold elections to create a veneer of legitimacy, but the process is controlled to ensure the regime's survival.

  • A change in leadership is a change in government, not necessarily regime. When a new prime minister takes office in the UK, the government changes, but the parliamentary democratic regime remains.

One-Paragraph Summary

The processes of changing power and authority reveal the core nature of a political system, distinguishing between a temporary government and the enduring regime. Democratic regimes, like the UK and Mexico, institutionalize peaceful government change through regular, competitive elections, which helps maintain sovereignty with broad legitimacy rather than force. In contrast, authoritarian regimes, such as China and Russia, manage government succession through controlled, non-competitive processes to ensure the regime's preservation. Major shifts in the fundamental rules of politics, or regime changes, can occur incrementally through elections, as in Mexico, or suddenly and violently through revolutions or coups, as seen in Iran and Nigeria. Ultimately, the method of political change—whether by ballot, appointment, or force—is a primary indicator of a state's democratic or authoritarian character.