(a) Describe separation of powers. (b) How does separation of powers operate under the presidential system of government?

(a) Separation of powers

Separation of powers is a constitutional principle, associated with the French political philosopher Baron de Montesquieu, which holds that the three organs of government, namely the legislature, the executive and the judiciary, should be kept separate and independent of one another. According to the principle, the same person or body should not exercise more than one of the three functions of government, and each organ should perform its own distinct function without interference from the others. The purpose is to prevent the concentration of power in one hand, guard against tyranny and dictatorship, and protect the liberty of the citizens.

(b) How separation of powers operates under the presidential system

1. Separate personnel: No person may belong to more than one organ at a time. A minister who is appointed into the executive cannot remain a member of the legislature, unlike in the parliamentary system.
2. Fixed and independent tenure: The President and the legislature are separately elected and each enjoys a fixed term. The President cannot dissolve the legislature, and the legislature cannot vote the President out through a simple vote of no confidence.
3. Distinct functions: The legislature makes the laws, the executive (President) implements and enforces the laws, and the judiciary interprets the laws and settles disputes, each within its own sphere.
4. Checks and balances: While the organs are separate, they check one another. The legislature makes laws but the President can veto bills; the President appoints judges and ministers but the legislature must confirm them; the legislature can impeach the President; and the judiciary can declare the acts of the executive or legislature unconstitutional through judicial review.
5. Independence of the judiciary: Judges enjoy security of tenure and cannot be easily removed, so that they can interpret the law and check the other arms without fear.

Thus, under the presidential system the principle operates not as a rigid, total separation, but as separated organs held together by a web of checks and balances.