Determining the constituency boundaries is an important step in the electoral process, since they can give rise to marked “structural” inequalities in representation. Three factors may be behind such disparities: demographic change, gerrymandering and “natural gerrymandering”.
- The varying demographic trends experienced by different territories make regular redrawing of constituency boundaries necessary. A failure to redraw constituencies has an adverse effect on the most demographically dynamic constituencies (urban areas) as compared with those constituencies with a low population growth (rural areas).
- Gerrymandering consists in skilfully redrawing constituencies on the basis of previous electoral results with a view to boosting the representation of the party in power. In such case, two specific examples may arise: either the minority is voluntarily brought together in a few constituencies where it has a strong majority, whilst the majority has only a slight edge over it in a higher number of constituencies; or the redrawing is carried out in such a way that the minority cannot obtain a majority in any constituency. In order to avoid this, it is absolutely necessary that the redrawing of constituency boundaries be carried out by an independent and politically neutral body.
- Lastly, there is what Maurice Duverger terms “natural gerrymandering”. Unlike gerrymandering proper, it does not result from a deliberately biased redrawing of boundaries. It may be that one category of the population is strongly concentrated in a small number of electoral constituencies, whilst another has a very small majority in a large number of constituencies.