The embargo has several different forms. The trade embargo prohibits the export of certain goods or services. The strategic embargo only prohibits the sale of military-related goods or services. In order to protect humans, animals and plants, a health ban has been issued. For example, health trade restrictions imposed by the World Trade Organization (WTO) prohibit the import and export of endangered animals and plants. Some trade embargoes allow the exchange of certain commodities, such as food and medicine, to meet humanitarian needs. In addition, most transnational embargoes contain provisions that allow certain exports or imports to be made based on a limited set of restrictions. Historically, most embargoes will eventually fail. While the restrictions imposed may successfully change the policies of democratic governments, citizens of countries under totalitarianism lack political power to influence their governments. In addition, totalitarian governments often do not care much about how trade sanctions hurt their citizens. For example, the United States’ trade embargo and economic sanctions against Cuba have been in place for more than 50 years, but have largely failed to change the repressive policies of the Castro regime.