Why must the legislative, executive and judicial powers be kept separate?

Translation: quotations from Montesquieu are quoted in Thomas Nugent's 1750 English translation; quoted in the anonymous 1777 English translation of the London Complete Works, not his original words.

1. WHAT HE SAID (the record)

Record ledger

• BELIEF (undated; quoted in Thomas Nugent's 1750 English translation): Montesquieu believed that the legislative, executive, and judicial powers must be kept separate to ensure political liberty. He argued that if these powers are united in the same person or body, liberty cannot exist because it leads to tyranny and oppression. (key quote above) [1]
• BELIEF (undated; quoted in Thomas Nugent's 1750 English translation): Montesquieu believed that if the executive power were committed to a certain number of persons selected from the legislative body, there would be an end of liberty, because the two powers would be united. He argued that the same persons would sometimes possess, and would be always able to possess, a share in both, which would endanger liberty. (key quote above) [2]
• BELIEF (undated; quoted in the anonymous 1777 English translation of the London Complete Works): Montesquieu believed that the greatest perfection of political liberty depends on the legitimate distribution and proper subdivision of different powers, particularly the legislative and executive. He argues that this is essential for maintaining political liberty in relation to the constitution. "It is from the legitimate distribution and proper subdivision of these different powers, that the greatest perfection of political liberty with relation to the constitution depends." [3]

What cuts against it

• ACTION (undated): Montesquieu did not explicitly address the practical implementation of power separation in monarchies where the executive and legislative powers are held by the same monarch, as in some European kingdoms. [1]

• ACTION (undated): Montesquieu did not address the potential for power separation to fail in practice due to political alliances or institutional overlap. [2]

• ACTION (undated): Montesquieu did not address the potential for power separation to be undermined by the influence of wealth or social class. [4]

• ACTION (undated): Montesquieu did not address the potential for power separation to be compromised in times of national crisis or emergency. [3]

2. HOW IT APPLIES (reasoning; inference is marked)

1. Montesquieu argued that political liberty requires the separation of legislative, executive, and judicial powers. [1]

2. He believed that if these powers are united in the same person or body, liberty cannot exist because it leads to tyranny and oppression. [1]

3. He provided the example of the decemvirs in Rome, who held all three powers and led to the people being enslaved by tyranny. [4]

4. He emphasized that the greatest perfection of political liberty depends on the legitimate distribution and proper subdivision of these powers. [3]

5. This principle is inferred to apply to any government structure where power concentration threatens individual freedoms. (inference)

3. HIS TAKE

Record coverage: DIRECT

Extrapolation: Montesquieu believed that the separation of powers is essential to prevent tyranny and ensure political liberty. He argued that when these powers are concentrated in one body or individual, it leads to oppression and the loss of liberty.

Competing readings: None.

Confidence: High, based on direct statements in the text.