The United States Constitution was adopted in 1789 and is the oldest written constitution still in effect.

In a parliamentary republic, the head of state is typically a president, who is elected by the parliament or by the people.

The United Kingdom has a unicameral legislature, meaning that it has only one chamber of parliament.

In a presidential system, the executive and legislative branches are separate and independent, meaning that the president is not a member of the legislature.

The United States has a federal system of government, meaning that power is divided between the federal government and the state governments.

In a military dictatorship, the military holds political power, often through a junta or a military leader.

The United Kingdom has a monarchy, with the monarch as the head of state.

In a theocracy, religious leaders hold political power, often through a religious law or a religious leader.

The United Kingdom has a parliamentary system of government, meaning that the prime minister is the head of government and is responsible to the parliament.

In a one-party state, a single party holds all political power, often through a dictatorship or a totalitarian regime.

The United States has a bicameral legislature, meaning that it has two chambers of parliament: the Senate and the House of Representatives.

In a democracy, the people hold political power, often through elections or referendums.

The United States has a presidential system of government, meaning that the president is the head of government and is responsible to the people.

In an oligarchy, a small group of wealthy individuals hold political power, often through a hereditary or financial elite.

The United Kingdom has a multi-party system, meaning that there are multiple political parties that compete for power in elections.