Though the legitimate use of force is presumed to be the realm of the state, during the 1990s and into the first decade of the twenty-first century, the private sector's role in security burgeoned. Global forces, new ideas, and political choices combined to enhance the opportunities for private delivery of and private financing for security services. A growing market for force now exists alongside, and intertwined with, state military and police forces.

I have argued that this development holds significant implications for the control of force that poses states, firms, and people with a number of trade-offs. Individual states can sometimes enhance the capacity of their forces, and thereby increase functional control. At the same time, though, the market undermines the collective monopoly of the state over violence in world politics, and thus a central feature of the sovereign system. Without that collective monopoly, states face increasing dilemmas about whether to hire from the private sector for security and how best to regulate the export of security services. Furthermore, even as privatization may increase the capacity of some states, it also changes who has influence over the use of force. The changes in political control are most dramatic when transnational private actors finance violence in weak states, but apparent even when PSCs deliver security services to strong states. Moreover, though non-state actors gain influence over force when they finance it, along with that influence comes responsibility for the behavior of the forces they finance – a development that frequently leads to political debates within communities of non-state actors.