Montesquieu's theory of separation of powers: merits, criticism and validity today

1. The idea

Government performs three functions: making law, executing it and adjudicating disputes under it. The theory of separation of powers holds that these functions should be vested in three distinct organs, the legislature, the executive and the judiciary, each staffed by different persons and none exercising the functions of another, because the concentration of all power in one hand is the definition of tyranny.

2. Antecedents

• Aristotle (Politics) distinguished three elements of every constitution: the deliberative, the magisterial and the judicial.
• Polybius praised the Roman Republic's mixed constitution, which balanced consuls, senate and assemblies.
• John Locke (Second Treatise of Government, 1690) separated the legislative, executive and federative (foreign relations) powers, warning that it would be too great a temptation for the same persons who make laws to have the power to execute them.

3. Montesquieu's theory

Charles-Louis de Secondat, Baron de Montesquieu, set out the theory in The Spirit of the Laws (De l'esprit des lois, 1748), Book XI, chapter 6, “Of the Constitution of England”. His concern was political liberty, which he defined as a tranquillity of mind arising from each person's sense of safety, and which needs a government under which no citizen need fear another. Liberty exists only where power is not abused, and “it is an eternal experience that every man who has power is led to abuse it.” So “power must check power” by the arrangement of things.

His central passage:

“When the legislative and executive powers are united in the same person, or in the same body of magistrates, there can be no liberty … Again, there is no liberty, if the judiciary power be not separated from the legislative and executive. Were it joined with the legislative, the life and liberty of the subject would be exposed to arbitrary control; for the judge would then be the legislator. Were it joined to the executive power, the judge might behave with violence and oppression. There would be an end of everything, were the same man or the same body … to exercise those three powers.”

He believed he had found this separation in the England of his day, after the Revolution of 1688. In fact he misread it: the King's ministers sat in Parliament, and the cabinet system was already growing. What he saw was the balance between King, Lords and Commons and the independence of the judges.

4. Influence

• The American Constitution (1787) is its fullest application. Article I vests legislative powers in Congress, Article II executive power in the President, Article III judicial power in the Supreme Court. Madison (The Federalist, No. 47) called the accumulation of all powers in the same hands “the very definition of tyranny”, and the framers added checks and balances: the presidential veto, Senate confirmation of appointments and treaties, impeachment, and judicial review.
• The French Declaration of the Rights of Man (1789), Article 16: “Any society in which the guarantee of rights is not assured, nor the separation of powers determined, has no constitution.”
• Most liberal constitutions since then have adopted some form of it.

5. Merits

1. Protects liberty by preventing the concentration of power.
2. Prevents arbitrary government: each organ checks the others.
3. Secures judicial independence, which is the part of the theory with the widest acceptance today.
4. Efficiency through specialisation: each organ does what it is fitted for.
5. Makes responsibility clear: one knows which organ is accountable for what.

6. Criticism

1. Historically mistaken. The British constitution was never based on separation; Walter Bagehot (The English Constitution, 1867) said its “efficient secret” was the close union, the nearly complete fusion, of the executive and legislative powers, through the Cabinet.
2. Complete separation is impossible. Government is an organic whole; its organs must co-operate. Every executive makes rules (delegated legislation), every legislature performs some judicial and executive acts, and judges make law through precedent.
3. It can cause deadlock: the American President and Congress, controlled by different parties, block each other, and government shutdowns follow budget disputes.
4. The three organs are not equal. Montesquieu assumed a balance, but in practice the legislature (Mill, Laski) or the executive (in the modern welfare state) dominates.
5. Liberty depends on other things: an independent judiciary, free press, free elections, rights, a vigilant public opinion. Britain has had liberty without separation.
6. Unsuited to the welfare state, which needs administrative tribunals combining functions, and quick, co-ordinated action.

7. Validity today

No country practises rigid separation. What survives is a functional separation with checks and balances, and above all the independence of the judiciary.

• USA: the nearest to the theory, but checks and balances mean that each organ shares in the others' functions.
• Britain: fusion of executive and legislature through the Cabinet, but an independent judiciary. The Constitutional Reform Act 2005 removed the Law Lords from the House of Lords and ended the Lord Chancellor's role as head of the judiciary, a step towards separation.
• India: the Constitution does not adopt separation in its rigid form; the executive is drawn from and responsible to Parliament. But it separates functions in broad terms: Article 50 directs separation of the judiciary from the executive, and the courts have held separation of powers to be part of the basic structure (Kesavananda Bharati v. State of Kerala, 1973 INSC 91; Indira Nehru Gandhi v. Raj Narain, 1975 INSC 272), so that Parliament cannot itself decide an election dispute or oust judicial review.

The conclusion most writers reach: the theory is invalid as a description and as a rigid prescription, but its central insight, that concentrated power endangers liberty and must be checked, remains valid and is built into every democratic constitution.

How this is examined

As a 6-mark note: the theory in Montesquieu's words, Locke as forerunner, the American application and two criticisms. As a 16-mark essay (“Examine Montesquieu's theory of separation of powers. Is it valid today?”), add the merits, the full criticism and the validity section with the three countries. Quote the central passage; it is short and earns marks.