Drawing Districts: Malapportionment and Gerrymandering

Where representatives are elected by district, how districts are drawn matters. Malapportionment occurs when districts have very unequal populations, so some votes count more than others. Britain's 'rotten boroughs', such as Old Sarum, which elected two MPs with almost no voters, were abolished by the Great Reform Act of 1832. The US Supreme Court required districts of roughly equal population in cases such as Reynolds v. Sims (1964).

Gerrymandering is drawing boundaries to benefit one party or group, by 'packing' opponents into a few districts or 'cracking' them across many. The term comes from Massachusetts governor Elbridge Gerry, who in 1812 signed a map with a salamander-shaped district. Responses vary: many countries, including the UK, Canada and Australia, use independent boundary commissions, while in the US, practice differs by state. Debate continues over how to balance fair representation, community ties and partisan interests.