In the United States, the head of state and the head of government are both embodied in the person of the President, but in many European countries, the two functions are fulfilled by different individuals. The European systems have developed from earlier monarchical structures that evolved through history to the present situation. Great Britain, France, and Germany each have these functions separated and embodied in different individuals, and the way these systems evolved differs as well as does the way the two roles function in each country.
The United Kingdom is a constitutional monarchy under a democratic parliamentary regime. The United Kingdom reached its greatest global influence in the Victorian era and then endured the strains of the two world wars without impairment to its political institutions but with a reduction in relative economic strength and military power. The constitutional monarchy operates without a written constitution on the basis of long-standing but flexible traditions. The British constitution is formed partly by statute, partly by common law, and partly by convention, and it can be altered by Act of Parliament or by general agreement to make a change. The organs of government are distinguishable but have functions that often overlap. The supreme authority is the legislature, Parliament. The executive branch consists of the Government, or the Cabinet and other ministers who are responsible for initiating and directing national policy; government departments, responsible for national administration; local authorities, which administer and manage many local services; and public corporations that are responsible for operating particular nationalized industries or a social or cultural service. The Queen is the head of state and also the symbol of the nation's unity. The institution has been broken only once during the last thousand years by the establishment of a republic from 1649 to 1660. In law...