"The importance of empire became especially obvious to the self-styled 'have not' powers when they adopted rearmament as a tool of economic recovery. For rearmament in the 1930s, if one wished to possess the most up-to-date weaponry, demanded copious supplies of a variety of crucial raw materials (see below). Neither Italy, Germany nor Japan had these commodities within their own borders other than in trivial quantities. By contrast, the lion's share of the world's accessible supplies lay within the borders of one of four rival powers: the British Empire, the French Empire, the Soviet Union and the United States. Thus, no country could aspire to military parity with these powers without substantial imports of commodities whose supply they all but monopolized. For three reasons, it was not possible for the 'have nots' to rely on free trade to acquire them. First, free trade had been significantly reduced by the mid-1930s, thanks to the imposition of protectionist tariffs. Second, Italy, Germany and Japan lacked adequate international reserves to pay for the imports they required. Third, even if their central banks' reserves had been overflowing with gold, there was a risk that imports might be interdicted by rival powers before rearmament was complete. There was therefore a compelling logic behind territorial expansion, as Hitler made clear in his memorandum of August-September 1936, which outlined a new Four-Year Plan for the German economy."