Parliamentary republics with an executive presidency in the context of "Semi-presidential system"

A government is the system or group of people governing an organized community, generally a state.

In the case of its broad associative definition, government normally consists of legislature, executive, and judiciary. Government is a means by which organizational policies are enforced, as well as a mechanism for determining policy. In many countries, the government has a kind of constitution, a statement of its governing principles and philosophy.

A military government is any government that is administered by a military, whether or not this government is legal under the laws of the jurisdiction at issue or by an occupying power. It is usually administered by military personnel.

A parliamentary system, or parliamentary democracy, is a form of government based on the fusion of powers. In this system the head of government (chief executive) derives their democratic legitimacy from their ability to command the support ("confidence") of a majority of the parliament, to which they are held accountable. This head of government is usually, but not always, distinct from a ceremonial head of state. This is in contrast to a presidential system, which features a president who is not fully accountable to the legislature, and cannot be replaced by a simple majority vote.

Countries with parliamentary systems may be constitutional monarchies, where a monarch is the head of state while the head of government is almost always a member of parliament, or parliamentary republics, where a mostly ceremonial president is the head of state while the head of government is from the legislature. In a few countries, the head of government is also head of state but is elected by the legislature. In bicameral parliaments, the head of government is generally, though not always, a member of the lower house.

A parliamentary republic is a republic that operates under a parliamentary system of government where the executive branch (the government) derives its legitimacy from and is accountable to the legislature (the parliament). There are a number of variations of parliamentary republics. Most have a clear differentiation between the head of government and the head of state, with the head of government holding real power and the head of state being a ceremonial position, similar to constitutional monarchies. In some countries the head of state has reserve powers to use at their discretion as a non-partisan "referee" of the political process. Some have combined the roles of head of state and head of government, much like presidential systems, but with a dependency upon parliamentary confidence. In general, parliamentary republics grant the highest sovereign powers to the parliament.

A presidential, strong-president, or single-executive system (sometimes also congressional system) is a form of government in which a head of government (usually titled "president") heads an executive branch that derives its authority and legitimacy from a source that is separate from the legislative branch. The system was popularized by its inclusion in the Constitution of the United States.

This head of government is often also the head of state. In a presidential system, the head of government is directly or indirectly elected by a group of citizens and is not responsible to the legislature, and the legislature cannot dismiss the president except in extraordinary cases. A presidential system contrasts with a parliamentary system, where the head of government (usually called a prime minister) derives their power from the confidence of an elected legislature, which can dismiss the prime minister with a simple majority.

A semi-presidential republic, or dual executive republic, is a republic in which a president exists alongside a prime minister and a cabinet, with the latter of the two being responsible to the legislature of the state. It differs from a parliamentary republic in that it has an executive president independent of the legislature; and from the presidential system in that the cabinet, although named by the president, is responsible to the legislature, which may force the cabinet to resign through a motion of no confidence.

While the Weimar Republic (1919–1933) and Finland (from 1919 to 2000) exemplified early semi-presidential systems, the term "semi-presidential" was first introduced in 1959, in an article by the journalist Hubert Beuve-Méry, and popularized by a 1978 work written by the political scientist Maurice Duverger. Both men intended to describe the French Fifth Republic (established in 1958).

This is a list of sovereign states by their de jure systems of government, as specified by the incumbent regime's constitutional law. This list does not measure the degree of democracy, political corruption, or state capacity of governments.