Politics in Minutes (2016)
Separation of powers
An important principle of democracy is the clear distinction between different branches of government - the legislature, the executive and the judiciary - and the separation of their powers. If these institutions of government, each with specific responsibilities and powers, function independently no single branch can exercise absolute power. The role of the legislature is to make the laws, the executive to carry them out and the judiciary to decide when they have been broken.
The theory of separation of powers is most strictly adhered to in republics such as the USA, where the executive branch of government is identified with the president, the head of state, the legislature with the Senate and House of Representatives, and the judiciary with the courts. In practice, however, the three branches of government are interlinked in presidential governments, and are even more closely tied in parliamentary systems, where the prime minister and cabinet have executive power and are at the same time part of the legislature.