Fusion of powers is a feature of some parliamentary forms of government where different branches of government are intermingled, typically the executive and legislative branches. It is contrasted with the separation of powers found in presidential, semi-presidential and dualistic parliamentary forms of government, where the membership of the legislative and executive powers cannot overlap. Fusion of powers exists in many, if not a majority of, parliamentary democracies, and does so by design. However, in all modern democratic polities the judiciary does not possess legislative or executive powers. The system first arose as a result of political evolution in the United Kingdom over many centuries, as the powers of the monarch became constrained by Parliament. The term fusion of powers itself is believed to have been coined by the British constitutional expert Walter Bagehot. One advantage of a fusion of powers, according to promoters, is that it is easier for the government to take action. There exists virtually no way for there to be a deadlock in the manner that can sometimes occur where the legislature and executive are separated. See, however, the 1975 Australian constitutional crisis for a counter-example (regarding the dual executive nature of some parliamentary systems). The disadvantage of a fusion of powers, paradoxically, is the power it gives to the executive branch, rather than the legislative branch. In a fusion of powers, the head of government must have the confidence of a majority in the legislature. If the majority is made up of members of one's own party, the head of government can use these supporters to control the legislature's business, thus protecting the executive from being truly accountable and at the same time passing any laws expedient for the government. A revolt by members of the government's own party (or, if the government is a coalition or minority government, by supporting parties) is possible, but party discipline, along with a tendency by many electorates to vote against unstable governments, makes such a revolt unattractive and therefore rare.