A referendum or plebiscite (plurals referenda, plebiscites) is a general poll on a legislative or constitutional issue.
Referendum is the referring of a political question to a direct vote of the electorate.
A consultative referendum (also called an advisory referendum) leaves the interpretation of the vote to the legislature.
A binding referendum is possible only in some countries, a certain size of the participating electorate often being a prerequisite.
A plebiscite is directed to all citizens, regardless of their franchise. A plebiscite, in its narrow sense, is the request for approval of a (radical) governmental decree or approval of the general policies of the government, typically in states without Democracy, Parliamentarism or a representative parliament.
Referenda are a key measure in semi-direct democracy and the only measure in a pure direct democracy. Few believe that such "rule by poll" is always desirable. For once, referendums may lead to inconsistent politics, such as increasing spending on certain issues while lowering taxes (both of which are likely to be favored by many voters). Voters may be subject to disinformation campaign, especially on emotional issues. Also, referendums may be inadequate for very technical issues. However, most advocates of grassroots democracy propose measures that would make them far more common.
In most jurisdictions practicing representative democracy, referenda, the calling of which can only be achieved through the act of a legislature, are a relatively rare event.
Constitutions, in many jurisdictions, are modifiable only by referendum. In part this is due to the arguments above, to ensure that the cases for and against change are concentrated at one point in time for a balanced presentation to the public.
However, in some jurisdictions, some non-constitutional issues are put to referenda, which can be initiated by a petition of a certain proportion of voters. One such measure is representative recall which permits voters (or party members) in one district to "fire" their elected representative. This would require a referendum only in the firing district.
See also: initiative, approval voting, political science, representative recall