This research note considers the effects of electoral system reform
in Bolivia. In 1995, Bolivia moved from a list-proportional to a mixedmember
proportional electoral system. The intervening years saw growing
regional polarization of politics and a collapse of the existing party system.
Using statistical analysis of disaggregated electoral data (at department, municipality, and district level), this paper tests whether electoral system reforms
may have contributed to the current political crisis. Research findings
show that regional cleavages existed prior to electoral system reform, but
suggest that reforms aggravated their effects. Such evidence gives reason to
question the recent popularity of mixed-member proportionality.