Although much of the information presented here concentrates on the possibilities of deliberate 'electoral engineering,' it is worth remembering that most electoral systems are not deliberately chosen. Often, the choice of electoral system is accidental.
Accidental choices are not necessarily poor ones; in fact sometimes they can be surprisingly appropriate. One example of this was the highly ethnically fragmented democracy of Papua New Guinea, which inherited the alternative vote from its colonial master, Australia, for its first three elections in the 1960s and 1970s. Because this system required voters to list candidates preferentially on the ballot paper, elections encouraged a spectrum of alliances and vote trading between competing candidates and different communal groups, with candidates attempting to win not just first preferences but second and third preference votes as well. This led to cooperative campaigning tactics, moderate positions, and the early development of political parties. When this system was changed, political behaviour become more exclusionary and less accommodating, and the nascent party system quickly unraveled.
With the benefit of hindsight, PNG thus appears to have been the fortuitous recipient of a possibly uniquely appropriate electoral system for its social structure. Most accidental or evolutionary choices are, however, more likely to lead to unintended consequences - particularly for the actors who designed them. For example, when Jordan adopted the SNTV in 1993, on the personal initiative of King Hussein, it not only of increased minority representation but also of facilitated the election of Islamic fundamentalists to the legislature, see Jordan - Electoral System Design in the Arab World. Many fledgling democracies in the 1950s and 1960s adopted copies of the British system, despite consistent misgivings from Westminster that it was 'of doubtful value as an export to colonies in Africa and Asia.' The sorry history of many such choices has underlined the importance of designing electoral and constitutional rules for the specific conditions of the country at hand, rather than blithely assuming that the same 'off the shelf' constitutional design will work identically in different social, political, or economic consequences.
