The "accumulation theory" adopted by Karl Kautsky, John A. Hobson and popularized by Vladimir Lenin centered on the accumulation of surplus capital during and after the Industrial Revolution: restricted opportunities at home, the argument goes, drove financial interests to seek more profitable investments in less-developed lands with lower labor costs, unexploited raw materials and little competition. Hobson's analysis fails to explain colonial expansion on the part of less industrialized nations with little surplus capital, such as Italy, or the great powers of the next century—the United States and Russia—which were in fact net borrowers of foreign capital. Also, military and bureaucratic costs of occupation frequently exceeded financial returns. In Africa (exclusive of what would become the Union of South Africa in 1909) the amount of capital investment by Europeans was relatively small before and after the 1880's, and the companies involved in tropical African commerce exerted limited political influence.