In the USA after the Prohibition (1920-1933) introduced regulation of a three-step system for the distribution of alcoholic beverages. According to this regulation, manufacturers (breweries, wineries, distilleries, importers), wholesalers and retailers may not be in the same hand and must be separated from each other. However, there are many exemptions in different states. For example, in some states, wineries and brewpubs (restaurants with their own brewery) may sell directly. In some states there is a restriction to only two levels (two-tier system). As a rule, manufacturers grant exclusive rights to market their products to one distributor within a geographical area, so that competition between two distributors cannot occur. A 2005 Supreme Court ruling allowed direct mail order to the states of Michigan and New York, thus creating a precedent case. See Direct shipping.