A Government That Checks Itself
Can a country be run well even if its leaders are not good people? Immanuel Kant thought so. He argued that the problem of setting up a state can be solved as long as it has the right constitution, one that does not depend on everyone behaving well. The trick is a constitution that pits opposing groups against each other, so that each keeps the others in line.
That idea sits at the heart of the separation of powers. It splits the work of government into separate jobs, usually making laws, carrying them out and judging cases. Each job goes to a different body, and each body keeps to its own role.
The idea is closely tied to checks and balances, where each branch can hold the others back. James Madison put the problem simply. People must be governed by other people, so a government has to be able to control those it governs, and it must also be made to control itself.
From Rome to a Short-Lived English Constitution
The roots go back to the ancient world. The writer Polybius described the Roman Republic as a mixed government, shared between the Senate, the Consuls and the Assemblies. He explained in detail how each part checked the others. He credited Lycurgus of Sparta with creating the first government of this kind.
Centuries later, during the English Civil War, supporters of Parliament saw England's government as three branches: the King, the House of Lords and the House of Commons. In their view, the King should only carry out the laws, while the two houses should make them.
In 1653 the English general John Lambert wrote the Instrument of Government, one of the first documents to propose a three-part split. It served as England's constitution for a few years. It set up a Parliament plus two executive bodies, the Council of State and the Lord Protector. All were elected, though the Lord Protector was elected for life. Later, after the Crown used the courts against opposition leaders in the 1680s, English thinkers began arguing that judges should be separate from the executive too.
Locke's Three Powers
In his Two Treatises of Government (1690), John Locke split power into three kinds. Legislative power decides how the force of the commonwealth is used. Executive power carries out the laws that are in force. The third, federative power, covers war and peace, alliances and all dealings with outsiders. Today we would call it foreign policy.
Locke separated the powers, but not necessarily the institutions. One person or body could hold two or more of them. He noted that executive and federative power, though different, were often held by the same institution.
For Locke, the lawmakers came first. "For what can give laws to another, must need to be superior to him," he wrote. That power came from the people, who had the right to make and unmake the legislature. Still, it had limits. It could not rule arbitrarily, raise taxes or take property without the consent of the governed. It also could not hand its law-making power to another body, an idea now called the nondelegation doctrine.
Montesquieu's Warning
The three-branch model most people know is linked to the French Enlightenment thinker Montesquieu. In The Spirit of Law (1748), he described power shared among a legislature, an executive and a judiciary. Oddly, he never used the term "tripartite system." He spoke of the "distribution" of powers instead.
He drew on two models. He believed the Roman Republic had split its powers so that no one could seize complete control. In Britain, he saw power divided among the monarch, Parliament and the courts. His rule was firm: each power should do only its own job, or "there would be an end to everything."
His reasoning was practical. If one person or body both made and carried out the laws, it could pass tyrannical laws and enforce them too. Judges who also made laws would rule arbitrarily, and judges who also ran the state would be oppressive. He gave the executive to a monarch because it must act quickly, which one person does best. Making laws, he felt, was better handled by many.
Checks, Balances and Extra Branches
Most modern constitutions blend the separation of powers with checks and balances. Each branch gets some influence over the others, so it can block or slow them down. Many parliaments, for example, are bicameral, and both houses must pass a bill before it becomes law. The United States built this approach into its Constitution in 1787.
In Federalist No. 78, Alexander Hamilton, citing Montesquieu, treated the courts as a fully separate branch. Before that, many colonists saw judges as add-ons to the executive. The system has a cost, though. When the people holding a veto in each branch do not agree, the result can be gridlock.
Not every country stops at three branches. Bolivia, Costa Rica, Panama, Nicaragua and Venezuela give the running of elections its own separate branch. In Taiwan, a body called the Control Yuan audits the government and can impeach officials for misconduct. In contrast stands fusion of powers, where one person or branch plays a major part in more than one function.
