  Luxemburg’s political stance is grounded in her analysis of capital as a set of economic, political and social relations with global scope. She developed her contribution to Marxist political economy in The Accumulation of Capital: A Contribution to the Economic Explanation of Imperialism (1913) and in her Introduction to Political Economy published posthumously in 1925 and based on her lectures on the same subject at the SPD party school. Her starting position is that the core of a capitalist economy is the extraction of surplus value and the exploitation of workers as a source of accumulation of profits. As Luxemburg puts it, the distinctive feature of a capitalist system of production consists in the fact that “only those goods are produced which can with certainty be expected to sell, and not merely to sell, but to sell at the customary profit” (Luxemburg 1913 [AK: 35]). To understand how this is possible, she argues, we need to focus on total capital and its continuous transformation from commodity to money and back to commodity again, in a new cycle of spiralling profits (Bellofiore 2009). What is required to maintain the capitalist system, Luxemburg shows, is firstly the ability of capitalists to make profit guaranteed by the reproduction of capitalism as a system; secondly, enough demand to meet the offer of new capitalist commodities brought into the market; and thirdly an incentive to accumulate based on the prospect of new markets to absorb increasing production.