Rothbard began to consider himself a "private property anarchist" in 1950 and later began to use "anarcho-capitalist" to describe his political ideology. In his anarcho-capitalist model, the system of private property is enforced by protection agencies, which compete in a free market and are voluntarily supported by consumers who choose to use their protective and judicial services. Anarcho-capitalists describe this as "the end of the state monopoly on force". He later came to terms that anarchism identified with socialism, and wrote that individualist anarchism is different from anarcho-capitalism and other capitalist theories due to the individualist anarchists retaining the labor theory of value and socialist doctrines, suggesting a new term to identify himself: "nonarchist".