 Modern-day proponents such as Andrew Linklater, Robert W. Cox and Ken Booth focus on the need for human emancipation from the nation-state.Hence, it is "critical" of mainstream IR theories that tend to be both positivist and state-centric.Further linked in with Marxist theories is dependency theory and the core–periphery model, which argue that developed countries, in their pursuit of power, appropriate developing states through international banking, security and trade agreements and unions on a formal level, and do so through the interaction of political and financial advisors, missionaries, relief aid workers, and MNCs on the informal level, in order to integrate them into the capitalist system, strategically appropriating undervalued natural resources and labor hours and fostering economic and political dependence.