Political Parties and Electoral Systems: Theory, History, and the Spanish Case

The Concept of the Political Party and its Historical Evolution

In his fundamental 1976 work entitled Partidos y sistemas de partidos, Giovanni Sartori explores the two antagonistic meanings of the word "party." The first conception identifies a party with the act of "partir," meaning to break, divide, or split. This view dominated political thought from Classical Athens until the late 18th century, where parties were seen as factions engaged in mutual destruction. This was viewed as a violation of "eunomía," which refers to stability, order, and adherence to the law. Classical authors believed democratic parties led to bad governance because collective decision-making mechanisms should be tempered by aristocratic republics where elites exercise power under legal and popular control. Factions were seen as threats to the consensus and the common good of the state.

The second conception identifies a party with "formar parte," meaning to integrate, articulate, or be part of a whole. This theoretical shift began in the late 18th century following the development of English parliamentarism and United States independence. In this view, political parties are seen as lines of opinion representing social plurality. Their function is to channel social demands toward the state through parliamentary debate and competition, rather than seeking the destruction of opponents. Since the late 19th century, with the universalization of the right to vote and the creation of mass parties, party systems have become essential to modern democracies. They regulate uncertainty in electoral competition, ensuring that no competitor denies the pluralistic nature of the democracy. However, since the 2008 economic crisis, there has been a trend toward Carl Schmitt's "friend-enemy" logic, leading to intense ideological, emotional, and linguistic polarization, which raises the question of whether modern parties currently integrate or divide society.

Historical Factionalism and Pre-Modern Mechanisms for Institutionalization

History provides several examples of the evolution from destructive factions to institutionalized parties. In the Ancient World, Athens saw conflicts between the Pisistratos family and the Alcmaeonids (508-429 B.C.). Following the reforms of Solon and the tyranny of the Pisistratos family, Cleisthenes (an Alcmaeonid) introduced democratic reforms that were later deepened by Pericles. Despite these reforms, philosophers like Plato and Aristotle believed Pericles "prostituted" the people through demagoguery. Cleisthenes attempted to break factional power by "mixing" the population into districts where different tribes and families lived together, yet factionalism persisted through the control of districts like the Piraeus.

In the Roman Republic (88-44 B.C.), competition between elites intensified due to corruption and institutional decay. This led to conflict between the "Optimates," who sought to preserve senatorial power, and the "Populares," who led by adopting popular demands. These factions lacked formal organization or doctrines but represented informal hierarchies and military clients. While authors like Cicero defended the aristocratic republic, the conflict ultimately led to the transition from Republic to Empire. In the pre-modern era, Florence faced violent instability due to the conflict between the Pazzi and Medici families (1469-1492). Niccolò Machiavelli offered a revolutionary theoretical perspective on this, arguing that large republics like Rome are inherently conflictual. He posited that conflict is a sign of greatness and that the people must exercise control to ensure that elite competition does not destroy the state.

Modern republicanism emerged from conflicts between the monarchy and local elites, particularly in England between 1215 and 1688. Exceptional property-owning families represented in Parliament eventually triumphed over the monarch through civil wars. Montesquieu identified this as the birth of English parliamentarism and the principle of representation. This principle is defined by five criteria: individuals from a territory choose a representative; the representative must meet merit or eligibility criteria; they exercise representation under a fiduciary model where they take their own decisions based on general instructions; the exercise of power is periodic; and it is strictly circumscribed to the promulgation of laws. Finally, in the United States (1776-1789), James Madison addressed factionalism in the context of the 13 colonies. He argued that since the causes of factionalism (liberty and diversity of opinion) cannot be removed without destroying freedom, one must control its effects. This involves applying the principle of representation, subjecting representatives to public opinion to moderate ideas, maintaining a large electoral body to ensure plurality, and encouraging a diversity of parties to prevent local prejudices.

Evolution and Basic Typologies of Modern Political Parties

Modern parties have evolved through several historical stages characterized by different organizational logics. In the 18th and 19th centuries, David Hume observed the rise of parliamentary groups centered on lines of opinion. Unlike old factions based on family interests or dangerous abstract religious ideas, these parties articulated specific opinions and interests, such as those favoring the Court or the Country, or the balance between authority and liberty. These groups allowed for the stability of the British parliamentary regime by moderating conflict.

As the right to vote expanded, Max Weber identified the "party of notables" (or cadres), which were groupings of individuals with high social or economic status. Maurice Duverger further defined these as being organized through local electoral committees that eventually formed a central committee. They consist of few members who provide prestige, technical experience, and funding. These parties are characterized by ideological flexibility, low party discipline, and local committee autonomy. In contrast, the universalization of the male vote led to "mass parties." Weber described the mass party as a "bureaucratic party" aimed at internal rationality, membership recruitment, professionalization of staff, and hierarchical structures governed by written rules and discipline. Weber also acknowledged the American "business-firm party" or electoral machinery, which seeks electoral efficiency through a political entrepreneur's investment and the mobilization of clients to capture votes.

The Relationship Between Electoral Systems and Party Systems

The electoral system serves to translate votes into seats, which creates a tension between governability (the ability to form stable governments) and pluralism (the accurate representation of social diversity). In a broad sense, an electoral system includes the electoral administration, financial regulations, and rules for counting votes. In a restricted sense, it refers to the formula for converting votes into representation. Maurice Duverger established the "Bronze Law" of electoral systems, identifying causal relationships: plurality (single-round) majoritarian systems produce two-party systems; two-round majoritarian systems produce multi-party systems; and proportional systems produce multi-party systems.

Duverger argued that majoritarian systems exert a mechanical factor that forces candidates to merge into two blocks for efficiency. Proportional systems, while tending toward multi-partyism, do not necessarily cause instability because they often dualize into coalitions and encourage voters to cast "useful votes" for larger parties. Distortions in these laws often depend on district size. Dieter Nohlen categorized constituencies as small (2 to 5 seats), medium (6 to 9 seats), or large (10 or more seats). He noted that proportional formulas, such as the D'Hont Law used in Spain, only function correctly in large districts; in small districts, they tend to favor majorities and act more like majoritarian systems.

Case Study: The Effective Number of Parties in Spain (1977-2023)

The Effective Number of Parties (NEP) is calculated using the Laakso-Taagepera index, where the Electoral NEP (ENEP) is $1 / \sum v_i^2$ using the proportion of votes, and the Parliamentary NEP (ENPP) is $1 / \sum s_i^2$ using the proportion of seats. Data for Spain is as follows:

1977: NEP (Votes) $3.94$, NEP (Seats) $2.89$ 1979: NEP (Votes) $3.79$, NEP (Seats) $2.81$ 1982: NEP (Votes) $3.00$, NEP (Seats) $2.33$ 1986: NEP (Votes) $3.25$, NEP (Seats) $2.68$ 1989: NEP (Votes) $3.69$, NEP (Seats) $2.85$ 1993: NEP (Votes) $3.20$, NEP (Seats) $2.67$ 1996: NEP (Votes) $3.10$, NEP (Seats) $2.72$ 2000: NEP (Votes) $2.85$, NEP (Seats) $2.48$ 2004: NEP (Votes) $2.81$, NEP (Seats) $2.50$ 2008: NEP (Votes) $2.61$, NEP (Seats) $2.34$ 2011: NEP (Votes) $3.22$, NEP (Seats) $2.60$ 2015: NEP (Votes) $5.48$, NEP (Seats) $4.53$ 2016: NEP (Votes) $4.82$, NEP (Seats) $4.16$ 2019 (April): NEP (Votes) $5.86$, NEP (Seats) $4.94$ 2019 (Nov.): NEP (Votes) $5.93$, NEP (Seats) $4.68$ 2023: NEP (Votes) $\approx 5.2$, NEP (Seats) $\approx 4.3$

Values between 1.0 and 1.8 indicate a dominant party system; 1.8 to 2.4 indicate a two-party system; 2.5 to 4.5 indicate moderate multi-partyism; and values over 5 indicate atomization. Traditionally, Spain was described as an "imperfect bipartisanship" because only two parties had executive options, despite the D'Hont Law's proportional design. This is largely because 26 out of 52 Spanish constituencies are "small" (2 to 5 seats). The system changed after the 2008 crisis and the 2014 European elections. Fragmentation increased due to the territorial cleavage (nationalist and regionalist parties being very efficient in specific districts) and the Catalan conflict in 2015-2016. In the 2023 elections, the data suggests a possible readjustment toward reordering.

Giovanni Sartori's Typology of Party Systems

Sartori emphasizes that the number of parties is not just a quantitative measure but a qualitative one based on which parties "count." A party counts if it has "coalition capacity" (necessary for forming or supporting a government) or "blackmail capacity" (the ability to intimidate or influence the decisions of other competitors even if not in government). Sartori's classification includes non-competitive systems: Single Party (totalitarian or authoritarian, like the USSR) and Hegemonic Party (where satellite parties exist but are subordinate, such as in the PRI-era Mexico or communist Poland).

Competitive systems include: Predominant Party (free elections where one party repeatedly wins an absolute majority, like Japan's LDP or India’s Congress party); Bipartisanship (alternation between two main parties that govern alone, like the US or UK); Moderate Pluralism (3 to 5 parties with low ideological distance and coalitional tendencies); Polarized Pluralism (5 or more parties with high ideological distance and anti-system parties, where competition is centrifugal toward the extremes, such as Italy’s First Republic); and Atomized (extreme fragmentation where no single party influences the system dynamics).

Modern Organizational and Ideological Classifications

Parties can be classified using organizational, ideological, or systemic criteria. Organizational types include the "Catch-all" party (Otto Kirchheimer), which is a mass party derivation with reduced membership, centered on leadership and electoral motives. The "Cartel party" (Katz and Mair) focuses on public office and state colonization, limiting external competition. "Movement parties" (Donatella della Porta) are organized around social movements with assembly structures and porous boundaries. "Platform parties" (Paolo Gerbaudo) use digital apps and social networks, often under a "hyper-leadership."

From an ideological perspective, parties are categorized by traditional clivages (conservative, socialist, ecologist, etc.) or territorial clivages (state-wide vs. nationalist/regionalist). "Protest parties" focus on situational conflicts and may derive into populism. "Niche" or thematic parties focus on specific issues like feminism or the environment. Regarding their position in the system, "Mainstream" parties are systemic and loyal, categorized by Wolfgang Müller and Kaare Strøm as "vote-seeking," "office-seeking," or "policy-seeking." Juan Linz distinguished between "semi-loyal" parties (willing to excuse anti-system actors) and "disloyal" parties (which explicitly boicott institutions). "Challenging" parties (Müller-Rommel) are systemic but propose fundamental institutional changes.