The people collectively choose the legislative branch of the government — usually the parliament (or a lower house of that body). Voters typically vote for the party they want represented in the legislature, and the majority party selects an individual to be the Prime Minister and department ministers. If the majority party does not have enough votes to govern alone, they often form coalitions with other parties. The ceremonial head of state is a hereditary monarch in a constitutional monarchy, or an elected president or chancellor in a republic.

The system of voting — for example, plurality or proportional representation — affects how the seats are allocated. Proportional representation systems include the largest remainder and highest average methods, which allocate seats based on either an idealized seats-to-votes ratio or by dividing each party’s total vote share into multiple electoral quotas, then awarding the seats to those parties with the biggest proportional shares of those quotas.

The most important limiting factor in the system is that the prime minister, in most cases, retains unconstrained power to call elections whenever he or she chooses. This can lead to periods of legislative gridlock. This problem can be mitigated by requiring that the prime minister obtain the consent of the House of Commons to dissolve parliament, or through provisions that allow for the election of an independent governor-general who is capable of dissolving the legislature. Also, by limiting the number of times that parliament may be dissolved within a four-year electoral cycle, or through introducing an absolute term limit for the prime minister.