World Politics: Electoral and Party Systems

Political Institutions: Electoral and Party Systems\n\n### Class Outline Overview\nThis lecture covers electoral and party systems as core political institutions, building on previous discussions of democratization and political regimes. The sequence of topics includes:\n* Democratization recap.\n* Political Institutions.\n* Electoral Systems (Types, examples, effects, and trade-offs).\n* Parties and Party Systems (Types, origins, Duverger's laws, demand via social cleavages, supply via electoral systems).\n\n### What are Political Institutions?\nPolitical institutions are the rules that structure political and social interaction by constraining and enabling actors' behavior. They are categorized into:\n* Formal Institutions: Created, communicated, and enforced through official channels, typically laws.\n * Examples include electoral rules (codified in regular laws) and the form of government (presidential or parliamentary, codified in the constitution).\n* Informal Institutions: Socially shared, unwritten rules, created, communicated, and enforced outside officially sanctioned channels.\n * Examples: The filibuster in the US Congress, paying bribes for government contracts, and presidential candidates accepting electoral results.\n\n### Electoral Systems\nElectoral systems are the set of rules and regulations for transforming votes into seats in a legislature. They crucially shape three functions of democratic government:\n1. Representation: Determines how many parties exist to meet the diverse and conflicting demands within society.\n2. Accountability: Defines the type of control citizens have over their representatives.\n3. Government Effectiveness: Impacts how effective the government is at making decisions (a key factor in the presidentialism vs. parliamentarism debate).\n\nEssentially, electoral systems dictate how democracy works.\n\n### Electoral System Families and Types\nElectoral systems are broadly categorized into majoritarian, proportional (PR), and mixed systems. Within these, many specific types exist, such as:\n* Majoritarian: Plurality (Single-Member District Plurality, Single Nontransferable Vote, Block Vote, Party Block Vote, Borda Count, Modified Borda Count, Limited Vote), Absolute Majority (Alternative Vote, Two-Round Systems (TRS): Majority-Runoff, TRS: Majority-Plurality).\n* Proportional (PR): Divisor (D'Hondt, Sainte-Laguë, Modified Sainte-Laguë, Imperiali, Reinforced Imperiali), Quota (Hare, Droop, Hagenbach-Bischoff), Single Transferable Vote, List PR.\n* Mixed: Independent, Dependent, Coexistence, Supposition, Fusion, Correction, Conditional.\n\nThese systems are used in national-level legislative elections globally.\n\n### Four Dimensions of Electoral Systems\nThe specific type of an electoral system results from considering four key dimensions:\n1. District Magnitude: The number of seats filled in each electoral district.\n2. Electoral Formula: The mathematical formula used to translate votes into seats.\n3. Ballot Structure: The number and type of choices available to voters on the ballot.\n4. Threshold: The minimum vote share a party needs to obtain a seat.\n\n### Plurality Rule (First Past the Post)\n* Mechanism: Voters cast a single vote for a candidate in a single-member district. The candidate with the highest number of votes wins the seat.\n* District Magnitude: One.$(DM=1)$\n* Electoral Formula: Plurality (