As originally conceived, a Constitutional Monarch was quite a powerful figure, head of the executive branch even though his or her power was limited by the Constitution and the elected parliament. Some of the framers of the US Constitution may have conceived of the president as being an elected Constitutional Monarch, as the term was understood in their time, following Montesquieu’s account of the separation of powers. The present concept of constitutional monarchy developed in the United Kingdom, where it was the democratically elected parliaments, and their leader, the prime minister, who had become those who exercised power, with the monarchs voluntarily ceding it and contenting it themselves with the titular position.

In many cases even the monarchs themselves, while still at the very top of the political and social hierarchy, were given the status of “servants of the people” to reflect the new, egalitarian view. In the course of France’s July Monarchy, Louis-Philippe I was styled “King of the French” rather than “King of France”. Following the Unification of Germany, Otto von Bismarck inspired, the Kaiser retained considerable actual executive power, and the Prime Minister needed no parliamentary vote of confidence and ruled solely by the imperial mandate. However, this model of constitutional monarchy was discredited and abolished following Germany’s defeat in the First World War. Later on, Fascist Italy could also be considered as a “Constitutional Monarchy” of a kind, in the sense that there was a king as the titular head of state while actual power was held by Benito Mussolini under a Constitution. This eventually discredited the Italian Monarchy and led to its abolition in 1946.  After the Second World War, surviving European monarchies almost invariably adopted some variant of the Constitutional Monarchy model originally developed in Britain.

In present terms, the difference between a parliamentary democracy that is a Constitutional Monarchy and one that is a republic is considered more a difference of detail than of substance. In both cases, the titular head of state – Monarch or President – serves the traditional role of embodying and representing the nation, while the actual governing is carried out by an elected Prime Minister. This is contradictory to the Republican cause and desire to abolish the role of the Monarch, to replace it with another individual to assume the same duties. Today Constitutional Monarchies are mostly associated with Western European countries such as the United Kingdom, Netherlands, Belgium, Norway, Denmark, Spain, Luxembourg, Monaco, Liechtenstein, and Sweden. However, the two most populous Constitutional Monarchies in the world are in Asia: Japan and Thailand. In such cases, it is the prime minister who holds the day-to-day powers of governance, while the King or Queen (or another monarch, such as a Grand Duke, in the case of Luxembourg, or Prince in the case of Monaco and Liechtenstein) retains only residual (but not always minor) powers. Different nations grant different powers to their monarchs. In the Netherlands, Denmark and in Belgium, for example, the Monarch formally appoints a representative to preside over the creation of a coalition government following a parliamentary election, while in Norway the King chairs special meetings of the cabinet. In nearly all cases, the Monarch is still the nominal chief executive but is bound by constitutional convention to act on the advice of the Cabinet. Only a few monarchies (most notably Japan and Sweden) have amended their constitutions so that the Monarch is no longer even the nominal chief executive.

The most significant family of Constitutional Monarchies in the world today are the sixteen Commonwealth realms under our Queen, Elizabeth II. Unlike some of their continental European counterparts, the Monarch and her Governors-General in the Commonwealth realms hold significant “reserve” or “prerogative” powers, to be wielded in times of extreme emergency or constitutional crises usually to uphold parliamentary government. An instance of a Governor-General exercising his power was during the 1975 Australian constitutional crisis, when the Australian Prime Minister of the time, Gough Whitlam, was dismissed by the Governor-General. The Australian Senate had threatened to block the Government’s budget by refusing to pass the associated appropriation bills. On 11 November 1975, Whitlam intended to call a half-Senate election in an attempt to break the deadlock. When he went to seek the Governor-General’s approval of the election, the Governor-General instead dismissed him as Prime Minister and shortly thereafter installed leader of the opposition Malcolm Fraser in his place.

Acting quickly before all parliamentarians became aware of the change of government, Fraser and his allies were able to secure passage of the appropriation bills, and the Governor-General dissolved Parliament for a double dissolution election. Fraser and his government were returned with a massive majority. This led to much speculation among Whitlam’s supporters as to whether this use of the Governor-General’s reserve powers was appropriate, and whether Australia should become a republic. Among supporters of constitutional monarchy, however, the experience confirmed the value of the Monarchy as a source of checks and balances against elected politicians who might seek powers in excess of those conferred by their respective constitutions, and ultimately as a safeguard against dictatorship. In Thailand’s Constitutional Monarchy, the monarch is recognized as the Head of State, Head of the Armed Forces, Upholder of the Buddhist Religion, and Defender of the Faith. The current King, Bhumibol Adulyadej, is the longest-reigning current Monarch in the world and in all of Thailand’s history. Bhumibol has reigned through several political changes in the Thai government. He has played an influential role in each incident, oftentimes acting as a mediator between disputing political opponents. (See Bhumibol’s role in Thai Politics.)

While the Monarch retains some powers from the Constitution, most particular is Lèse majesté which protects the image and ability of the monarch to play a role in politics and carries modest criminal penalties for violators. Generally, the Thai people are reverent of Bhumibol. Much of his social influence comes from that and the fact that the Royal family is often involved in socio-economic improvement efforts. In both the United Kingdom and elsewhere, a common debate centres around when it is appropriate for a Monarch to use his or her political powers. When a Monarch does act, political controversy can often ensue, partially because the neutrality of the Crown is seen to be compromised in favour of a partisan goal.

While political scientists may champion the idea of an “Interventionist Monarch” as a check against possible illegal action by politicians, the Monarchs themselves are often driven by a more pragmatic sense of self-preservation, in which avoiding political controversy can be seen as an important way to retain public legitimacy and popularity. There also exist today several federal Constitutional Monarchies. In these countries, each subdivision has a distinct government and head of government, but all subdivisions share a Monarch who is head of state of the federation as a united whole. The latest country that was completely transformed from an Absolute Monarchy to a Constitutional Democratic Monarchy in Bhutan.