Checks and balances

In politics, the principle of checks and balances underlies many democratic governments. The term was coined by Montesquieu during the Enlightenment. The principle is an outgrowth of the classical idea of separation of powers. The first national system of checks and balances was outlined by the United States Constitution in 1789.

A government is said to have an effective system of checks and balances if no one branch of government holds total power, and can be overidden by another.

In most nations with a three-branch government, the process of checks and balances works in a manner similar to this:

The executive branch approves the bills of the legislature into law, but retains the right of veto or suspension. It can also appoint judges and cabinent members, and can pardon citizens.
The legislative branch has the authority to impeach members of the executive or judicial branch from office, or force elections. It also confirms or denies executive and judicial appointees, and can override vetos. In many countries, members of the executive, including the cabinet are also selected directly from the legislature.
The judiciary's primary function is to ensure that the laws passed by the government are obeyed. It can also throw out laws it deems illegal, or unconstitutional.

Thus, each branch has some level of control over the other, and all three are necessary for the government to function properly.