Proportional Representation and Coalition Governments

Proportional representation, or PR, is an electoral system that aims to give parties seats broadly in proportion to their share of votes. A coalition government is formed when two or more parties jointly exercise governmental power. PR encourages coalitions because it makes it easier for several parties to enter the legislature and less likely that one party will secure a majority alone.

How proportional representation shapes the legislature

PR reduces the gap between a party's vote share and its seat share, allowing a wider range of political preferences to obtain representation.

• Under party-list PR, seats are allocated among party lists broadly according to their vote shares, subject to the electoral rules.
• Unlike first-past-the-post, PR does not generally give a party a large seat advantage merely because it finishes first in many constituencies.
• Smaller parties with geographically dispersed support have better prospects of winning representation, rather than needing to finish first in individual constituencies.

Why several parties lead to coalition bargaining

A parliamentary executive must retain the confidence of the legislature, usually its popularly elected house. Where no party commands a majority, parties have an incentive to negotiate support.

• A fragmented distribution of seats can produce a hung parliament, in which no single party has an absolute majority.
• Parties may combine their seats to establish a majority and agree on ministerial positions, policy priorities and arrangements for resolving disagreements.
• Smaller parties can become important bargaining partners when their support is necessary to assemble or sustain a governing majority.

Why coalitions are likely, not inevitable

The connection is a tendency, not a rule: electoral systems shape party competition but do not determine voter preferences or government formation.

• A party with sufficiently broad support can win a majority under PR, while first-past-the-post can also produce coalition governments.
• Electoral thresholds, which require a minimum vote share for representation, can restrict the entry of very small parties.
• A party may instead form a minority government sustained by outside support, without bringing supporting parties into the cabinet.
• Coalitions can widen representation and encourage compromise, but disagreements among partners can complicate decisions and blur responsibility for government policy.