"Congress's role and operation in national politics is fundamentally shaped by the design and structure of the governing institution in the Constitution. One of the key principles of the Constitution is separation of powers. The doctrine is rooted in a political philosophy that aims to keep power from consolidating in any single person or entity, and a key goal of the framers of the Constitution was to establish a governing system that diffused and divided power. These objectives were achieved institutionally through the design of the Constitution. [...] This report provides an overview of separation of powers. It first reviews the philosophical and political origins of the doctrine. Then it surveys the structure of separation of power in the Constitution. It next discusses the consequences of the system, for both the institutions and for individual political actors. Finally, there is a discussion of separation of powers in the context of contemporary politics."
CRS Report for Congress, R44334
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html