What Is a Political Party? Definition, Functions and Types

A simple definition

Britannica defines a political party as a group of persons organized to acquire and exercise political power. That short definition captures what separates a party from other political groups. An advocacy group or a think tank tries to influence government. A party tries to become the government, by running candidates under its own name.

Most parties share a few features:

• A name and a label that candidates carry on the ballot.
• A program or platform that, as Britannica puts it, defines the party's ideology and sets out the agenda it would pursue in office.
• An organization of officials, activists, donors and members that outlasts any single election.
• A goal of winning office, not just shaping debate.

If you want to see how this works in one country, our guide to political parties in the US walks through the Democrats, the Republicans and the main minor parties.

Three classic views of parties

Thinkers have long disagreed about what a party really is. Three definitions still shape the debate.

Burke: a party of principle

In Thoughts on the Cause of the Present Discontents (1770), Edmund Burke defended the Rockingham Whigs and gave the most famous principled definition:

A party is "a body of men united, for promoting by their joint endeavours the national interest, upon some particular principle in which they are all agreed." (Edmund Burke, 1770)

Burke drew a sharp line between a party, held together by a shared view of the common good, and a faction, bent on its own advantage.

Schattschneider: parties make democracy work

The American political scientist E. E. Schattschneider opened his book Party Government (1942) with the claim that "modern democracy is unthinkable save in terms of the parties." In his view, voters in a large country cannot choose among thousands of individual policies. Parties package those choices into a few clear options and make government answerable for them.

Downs: teams seeking office

The economist Anthony Downs, in An Economic Theory of Democracy (1957), took a more hard-headed view. He modeled parties as teams that want to win office, and that adopt policies mainly as a means to that end. This approach helped explain why parties in two-party systems often move toward the middle of the electorate, an idea explored in our guide to the two-party system.

The three views are not exclusive. Most real parties mix principle, problem solving and plain ambition.

What political parties do

Political scientists usually list four core functions.

1. Recruiting and nominating candidates. Parties find people to run, and through primaries, caucuses or internal votes, choose who carries the label.
2. Aggregating interests. A party pulls together many groups, such as unions, business owners, religious voters or environmentalists, and turns their demands into one program voters can accept or reject.
3. Organizing government. In a legislature, parties pick leaders, assign committee seats and line up votes. In parliamentary systems, the party or coalition with a majority forms the government.
4. Providing accountability. Because parties last longer than any one politician, voters can reward or punish them for how the country is run.

Parties also educate and mobilize voters, raise money, train activists and, in many countries, receive public funding to do all of this.

How parties formed

Organized parties are surprisingly recent. In 18th century Britain, loose groups called Whigs and Tories competed in Parliament, but they had little organization outside it.

The United States offers a clear case of parties forming despite the wishes of the founders. In Federalist No. 10, James Madison described "the mischiefs of faction" and argued that a large republic could control their effects. In his 1796 Farewell Address, George Washington issued "a solemn warning against the baneful effects of the spirit of party." The Senate Historical Office notes that parties had not yet become accepted as vital, opinion-focusing agencies, and that Washington saw in them the seeds of the nation's destruction.

Yet the founders themselves had already split. Supporters of Alexander Hamilton's strong national government formed the Federalists, while Thomas Jefferson and Madison organized the Democratic-Republicans. Parties turned out to be the practical tool for winning elections across a large country.

Britannica notes that cadre parties emerged in Europe and America in the 19th century. As voting rights expanded, new parties grew from outside parliament, often from labor unions, churches or farmers' movements.

Types of political parties

Comparative political scientists sort parties into a few broad models. These are ideal types, and Britannica notes that many parties combine features of more than one.

Cadre parties

French political scientist Maurice Duverger described cadre parties as groups of notables: elected officials, local leaders and wealthy backers. They had few formal members and came alive mainly at election time. Many 19th century liberal and conservative parties began this way.

Mass parties

Mass parties appeal to a whole section of the electorate and rely on large dues-paying memberships, local branches, newspapers and youth groups. Many socialist, social democratic and Christian democratic parties of the early 20th century fit this model.

Catch-all parties

In the 1960s, the German-American scholar Otto Kirchheimer argued that postwar parties in Western Europe were dropping their strong ideological identities. To win as many voters as possible, these catch-all parties stressed broad issues that few people oppose and leaned on popular leaders. Kirchheimer worried this would weaken real opposition.

Cartel parties

In a 1995 article in the journal Party Politics, Richard Katz and Peter Mair proposed a newer model. In their account, established parties increasingly rely on the state, through public funding and media access, and collude to protect their collective survival. A 2026 retrospective in the same journal called the cartel thesis one of the most common ideas in comparative party research, though scholars still debate how well it fits.

Party systems

A party system describes how many parties matter in a country and how they compete.

• One-party systems allow only one legal party, or one party that cannot realistically lose. Communist states are the best-known examples.
• Dominant-party systems hold competitive elections, but one party wins almost every time for decades.
• Two-party systems have two large parties that alternate in power, as in the United States. See our full guide to the two-party system.
• Multiparty systems have several parties that win seats, and governments are often coalitions. They are common in countries that use proportional representation, such as much of continental Europe.

Parties vs ideologies

A party is not the same thing as an ideology. An ideology such as liberalism, conservatism or libertarianism is a set of ideas about how society should work. A party is an organization that competes for power, and to win it must build coalitions.

That means most large parties hold several ideological wings at once. A center-right party may include fiscal conservatives, social conservatives and libertarians. A center-left party may include progressives, social democrats and moderates. In Europe, the same gap shows up in debates such as Christian democracy vs conservatism or democratic socialism vs social democracy.

It also means your personal views may not match any party exactly. Our list of political ideologies maps the main families of thought separately from any party label.

Party identification in the US

Americans increasingly say they are independent, yet most still behave like partisans. In a 2024 Pew Research Center analysis of registered voters, 33% identified as Democrats, 32% as Republicans and 35% as independents or something else. Most of that last group lean toward a party: 16% of voters lean Democratic and 15% lean Republican.

Feelings toward the other side have also grown sharper. In a 2022 Pew survey, 72% of Republicans and 63% of Democrats said members of the opposing party were more immoral than other Americans, up from 47% and 35% in 2016. The same survey found that 27% of Americans viewed both major parties unfavorably, up from 6% in 1994.

The case for and against parties

In their defense

Supporters, following Burke and Schattschneider, argue that parties are what make mass democracy possible. They give voters simple, meaningful choices, train future leaders, build coalitions across regions and groups, and give the public a clear target to blame or reward. Without parties, defenders say, politics would fall to celebrities, wealthy self-funders and narrow interest groups.

Criticisms from several directions

• From the founding tradition. Following Washington's warning, many critics argue that party loyalty puts the interests of a team above the country, and that partisanship turns fellow citizens into enemies.
• From the left. Some progressives argue that major parties depend on large donors and business interests, which narrows the choices voters actually get on economic policy.
• From the right. Some conservatives and libertarians argue that party establishments protect incumbents and careers, grow government regardless of who wins, and sideline grassroots voters.
• From the center and reformers. Many centrists and political reformers argue that primaries reward the most partisan voters, so parties nominate candidates who are further from the median voter.
• From political scientists. Cartel theorists warn that parties funded and protected by the state can become insulated from the voters they are supposed to represent.

Each critique comes with proposed remedies, from stronger parties to weaker ones, and from new voting systems to more parties. The two-party system guide covers those reform debates.

Find where you fit

Before you pick a party, it helps to know your own views. Party labels bundle many issues together, and most people agree with their party on some and not others.

Take the Political Compass Test to see where you sit on the economic and authority axes, or the Political Values Test for separate scores on economics, civil liberties, society and diplomacy. For a quick start, try the Left or Right Quiz. Then read what is my political ideology to put a name to the results.