How Do The UK And American Poltical Systems Differ?

With Donald Trump set to take office as the 47th President of the United States on Monday, January 20, 2025, attention naturally turns to the historic and strategic “special relationship” between the UK and the US. Popularised by Winston Churchill in 1944, this term highlights the exceptionally close political, security, cultural, historical, and economic ties shared by the two nations.

Yet, despite their many similarities, including a shared language and commitment to democracy, the political systems of the UK and the US differ in profound ways as I have shown here.

Republic vs. Constitutional Monarchy And Parliamentary Democracy

One of the most significant differences lies in the form of government. The UK is a constitutional monarchy and parliamentary democracy, where the monarch serves as a ceremonial head of state. Real political power rests with Parliament, led by the Prime Minister, who acts as head of government.

In contrast, the US is a federal republic and presidential democracy. The President is both head of state and head of government, with power distributed between the federal and state governments.

Written vs. Unwritten Constitution

The two countries also diverge in their approach to constitutional law. The US operates under a written constitution, a single codified document ratified in 1789, which explicitly defines the structure, powers, and limitations of government.

The UK, by contrast, relies on an unwritten constitution, a collection of statutes, conventions, legal judgments, and historical documents, such as the Magna Carta. This flexible framework allows for greater adaptability but lacks the rigidity and clarity of a codified system.

Devolved vs. Federal Power

The UK, as a unitary state, centralizes power in Parliament, though some powers are devolved to Scotland, Wales, and Northern Ireland. The US, on the other hand, operates under a federal system, sharing authority between the national government and individual states. This federal system reflects the sheer scale and diversity of the US, with a population of 340 million, five times that of the UK, and a landmass roughly 40 times larger. Centralised governance on this scale would be impractical, making federalism a necessity.

Judicial Power

Judicial authority is another key area of distinction. In the UK, the judiciary, including the Supreme Court, is independent but lacks the power to overturn parliamentary legislation, as Parliament is sovereign.

In the US, the judiciary wields significant influence through judicial review, allowing courts to invalidate laws or executive actions deemed unconstitutional.

Parliamentary vs. Presidential Elections

The electoral processes of the two nations also differ. In the UK, general elections are held at least every five years using a first past-the-post system. The Prime Minister is not directly elected by the public but is the leader of the majority party in Parliament.

In the US, federal elections occur every two years, with presidential elections held every four years. Citizens vote directly for electors in the Electoral College, who then elect the President. Members of Congress are directly chosen by voters, ensuring a clear separation between legislative and executive powers.

Legislative Structures

Both nations have bicameral legislatures (which means separated into two separate assemblies), but their compositions and powers vary.

In the UK, Parliament consists of the House of Commons, whose members are elected, and the House of Lords, an unelected chamber comprising life peers, bishops, and hereditary peers who provide legislative oversight.

In the US, Congress includes the House of Representatives, with members elected based on population, and the Senate, where each state elects two senators regardless of size. Unlike the UK Parliament, Congress operates independently of the executive branch.

While the UK and the US share a commitment to democracy and strong bilateral relations, their political systems reflect different, distinct historical contexts and governance philosophies. The UK’s parliamentary democracy emphasizes centralized authority and party discipline, whereas the USA’s presidential democracy prioritizes a separation of powers and federalism.