A mechanism which allows voters to make a choice between alternative courses of action on a particular issue. The result of the referendum may then be embodied in the particular state's constitution; it may be mandatory before an international treaty can be signed; it may serve as the equivalent of legislation; it may be necessary before public funds can be raised for a particular purpose; or it may simply be advisory. In some countries, such as Britain, the referendum has been effectively limited to big constitutional issues. In countries or states where there is more extensive use of the referendum, it is usual for a referendum question to be placed before the electorate if a given number or percentage of signatures can be obtained from electors in a specified time period, although there may also be provision for a referendum initiated by the head of government (as in France) or the legislature. Polities which make extensive use of the referendum, such as Switzerland or the state of California, encounter a number of difficulties. The ability of governments and legislatures to pursue coherent policies is weakened. Political parties become less important as mechanisms for developing policy options. Voters find it difficult to decide on complex issues, and may rely on politicians or the media to guide their choice, or use the referendum to make a general protest against current government policy. Too frequent use of the referendum may lead to ‘voter fatigue’ with declining turnout. Nevertheless, electors in those countries which use the referendum are generally reluctant to discard it. It can be defended as a means of ensuring that politicians do not lose touch with the preferences of the electorate.