Coexistence (electoral systems)

In political science, coexistence^[1] involves different voters using different electoral systems depending on which electoral district they belong to.^[2] This is distinct from other mixed electoral systems that use parallel voting (superposition) or compensatory voting. For example, the rural-urban proportional (RUP) proposal for British Columbia involved the use of a fully proportional system of list-PR or STV in urban regions, combined with MMP in rural regions.^[3]

A diagram of a coexistence based mixed electoral system combining first-past-the-post and party-list proportional representation.

Coexistence of electoral systems exist in multiple countries, like the Democratic Republic of the Congo and Panama, as well as for elections of the European Parliament.^{[citation needed]}. Historically, variants have been used in Iceland (1946–1959), Niger (1993, 1995) and Madagascar (1998).^[4]

Types of coexistence

Type	System	Example(s) for use
Coexistence	e.g. FPTP/SMP in single-member districts, list-PR in multi-member districts	Democratic Republic of the Congo, Panama
Supermixed	e.g. FPTP/SMP in single-member districts, conditional party block voting in multi-member districts	Cameroon, Chad
	Rural-urban proportional representation (RUP)	Denmark (formerly), Iceland (formerly)
	Seat linkage compensatory mixed system (MMP) and FPTP in special constituencies	Bolivia