The United States, Canada, the countries of the European Union, Australia, and Japan are examples of present core countries that have the most power in the world economic system. world map of countries by trading status, late 20th century, using the world system differentiation into core countries (blue), semi-periphery countries (purple) and periphery countries (red). Based on the list in Dunn, Kawano, Brewer (2000). Developed countries are shown in blue.