State policy, practice, or advocacy of extending power and dominion, especially by direct territorial acquisition or by gaining political and economic control of other areas. Because imperialism always involves the use of power, often in the form of military force, it is widely considered morally objectionable, and the term accordingly has been used by states to denounce and discredit the foreign policies of their opponents. Imperialism in ancient times is clear in the unending succession of empires in China, western Asia, and the Mediterranean. Between the 15th century and the middle of the 18th, England, France, the Netherlands, Portugal, and Spain built empires in the Americas, India, and the East Indies. Russia, Italy, Germany, the United States, and Japan became imperial powers in the period from the middle of the 19th century to World War I. The imperial designs of Japan, fascist Italy, and Nazi Germany in the 1930s culminated in the outbreak of World War II. After the war the Soviet Union consolidated its military and political control of the states of eastern Europe (see Iron Curtain). From the early 20th century the U.S. was accused of imperialism for intervening in the affairs of developing countries in order to protect the interests of U.S.-owned international corporations (see United Fruit Co.). Economists and political theorists have debated whether imperialism benefits the states that practice it and whether such benefits or other reasons ever justify a state in pursuing imperialist polices. Some theorists, such as Niccolò Machiavelli, have argued that imperialism is the justified result of the natural struggle for survival among peoples. Others have asserted that it is necessary in order to ensure national security. A third justification for imperialism, offered only infrequently after World War II, is that it is a means of liberating peoples from tyrannical rule or bringing them the blessings of a superior way of life. See also colonialism; sphere of influence.