Although some advocates of direct democracy would have the referendum become the dominant institution of government, in practice and in principle, in almost all cases, the referendum exists solely as a complement to the system of representative democracy, in which most major decisions are made by an elected legislature. An often cited exception is the Swiss canton of Glarus, in which meetings are held on the village lawn to decide on matters of public concern. In most jurisdictions that practice them, referendums are relatively rare occurrences and are restricted to important issues.
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Critics of the referendum argue that voters in a referendum are more likely driven by transient whims than careful deliberation, or that they are not sufficiently informed to make decisions on complicated or technical issues. Voters might furthermore be swayed by strong personalities, or the adverse influence of propaganda or expensive advertising campaigns. James Madison argued that direct democracy is the "tyranny of the majority."

Some opposition to the referendum has arisen from its use by dictators such as Adolf Hitler and Benito Mussolini who, it is argued, used the plebiscite to disguise oppressive policies in a veneer of populism. Hitler's use of the plebiscite is argued as reason why, since World War II, there has been no provision in Germany for the holding of referendums at the federal level.

http://en.wikipedia.org/wiki/Referendum