A constitutional monarchy, parliamentary monarchy, or democratic parliamentary kingdom is a form of monarchy in which the monarch exercises their authority in accordance with a constitution and is not alone in making decisions. Constitutional monarchies differ from absolute monarchies (in which a monarch is the only decision-maker) in that they are bound to exercise powers and authorities within limits prescribed by an established legal framework.
Constitutional monarchies range from countries such as Liechtenstein, Monaco, Morocco, Jordan, Kuwait, Bahrain and Bhutan, where the constitution grants substantial discretionary powers to the sovereign, to countries such as Australia, the United Kingdom, Canada, the Netherlands, Spain, Belgium, Norway, Sweden, Malaysia, Thailand, Cambodia, and Japan, where the monarch retains significantly less, if any, personal discretion in the exercise of their authority. On the surface level, this distinction may be hard to establish, with numerous liberal democracies restraining monarchic power in practice rather than written law; i.e. the constitution of the United Kingdom, which affords the monarch substantial, if limited, legislative and executive powers.
Constitutional monarchy may refer to a system in which the monarch acts as a non-party political head of state under the constitution, whether codified or uncodified. While most monarchs may hold formal authority and the government may legally operate in the monarch's name, in the form typical in Europe the monarch no longer personally sets public policy or chooses political leaders. Political scientist Vernon Bogdanor, paraphrasing Thomas Macaulay, has defined a constitutional monarch as "A sovereign who reigns but does not rule".
In addition to acting as a visible symbol of national unity, a constitutional monarch may hold formal powers such as dissolving parliament or giving royal assent to legislation. However, such powers generally may only be exercised strictly in accordance with either written constitutional principles or unwritten constitutional conventions, rather than any personal political preferences of the sovereign.