The Foreign Policy Analysis and the systemic study of International Politics seem to be fields that, due to their own nature, are separated from each other. However, this division is more artifi- cial than real. Parting from the agent-structure debate, this paper proposes that each of these parts constitutes itself in its relation with the other. This premise has its foundations on the notion that ideas have actual material effects: the actors' identities and the structures that define them. Hence, Role theory and Discursive Institutionalism provide alternatives to deal with a complex reality along three levels of analysis: unit-level, microstructure and macrostructure, which are mutually complementary, instead of excluding each other out.