ISC Class 12 · Forms of Government

Britain as a Unitary State and the USA as a Federal State (ISC Class 12 Political Science)

Updated 17 October 2026 · Fact-checked

In a unitary state all legal power rests with one central government; Britain is the standard example, because its sovereign Parliament can create, change or abolish every lower body. In a federal state the constitution itself divides power between a national government and state governments, and neither can take away the other's share; the USA is the standard example.

In Britain lower bodies get power from Parliament and can be changed; in the USA the Constitution gives national and state governments their own power.

Illustration drawn for QuestionBuddy.

Understand Britain as a Unitary State and the USA as a Federal State

Why this topic matters. The syllabus asks for the meaning and features of Britain as a unitary state, the meaning and features of the USA as a federal state, and a comparison of the two. Marks are lost when candidates describe the two states in general terms and do not tie each feature to Britain or the USA.

1. Meaning of the two terms.

Unitary state: a state in which sovereignty is vested in a single central government. Any local units exist because the centre created them, and the centre may widen or narrow their powers by ordinary law.
Federal state: a state in which the constitution distributes powers between a national (federal) government and the governments of the units (states). Each level is supreme in its own sphere and gets its authority from the constitution, not from the other level.

2. Britain as a unitary state: features.

1. Sovereignty of Parliament. The UK Parliament (the Crown in Parliament, the House of Commons and the House of Lords) is the supreme law-making body. No court can strike down an Act of Parliament, and no Parliament can bind a later one.
2. One central government. There is one national legislature and one national executive for the whole country. Local bodies (county, district and city councils) exist under Acts of Parliament.
3. Devolution is not federalism. Parliament has devolved some powers to a Scottish Parliament, a Welsh legislature and a Northern Ireland Assembly through Acts of 1998 (the Scotland Act, the Government of Wales Act and the Northern Ireland Act). Because these are ordinary Acts, Parliament could in law amend or repeal them; the devolved bodies do not hold a constitutionally protected share of power. This is why Britain is still called unitary.
4. Unwritten and flexible constitution. Because the constitution is changed by the same process as ordinary law, no tier has protected powers. (Compare the page on amending procedures.)
5. No court refereeing a division of powers. Since the constitution contains no fixed division between levels, the courts do not decide disputes between centre and units on that basis.
6. Single citizenship and a single set of national laws on the main subjects.

*Merits often listed:* strong and quick decisions, uniform laws, lower cost of government and no dispute between centre and units. *Limit:* the centre may neglect distant regions; devolution is the British response.

3. The USA as a federal state: features.

1. Written constitution (1787, in force 1789). The Constitution is the supreme law (Article VI, the Supremacy Clause). Both the Union and state governments are bound by it.
2. Division of powers. The Constitution lists powers given to the national government (for example, to tax, borrow, regulate trade among states and with foreign nations, declare war, coin money; Article I, Section 8). The Tenth Amendment says powers neither given to the Union nor denied to the states are reserved to the states or the people. Thus residuary powers lie with the states, the opposite of the Indian arrangement.
3. Rigid constitution. Amendment needs a two-thirds proposal in Congress (or a convention requested by two-thirds of state legislatures) and ratification by three-fourths of the states, so neither level can change the division alone.
4. Independent judiciary as umpire. The Supreme Court decides disputes between the Union and the states, and between states, and can declare laws of either level void if they violate the Constitution.
5. Two governments with their own territory of authority. Each of the fifty states has its own constitution, legislature, governor and courts. People are subject to both national and state law.
6. Bicameral Congress with equal state representation in the Senate. Each state, large or small, sends two Senators, which gives the states a voice in national government.
7. Dual citizenship. A person is a citizen of the United States and of the state of residence (Fourteenth Amendment).

4. Comparison.

Basis	Britain (unitary)	USA (federal)
Source of power of lower units	Act of the central Parliament	The Constitution
Sovereignty	With Parliament alone	Divided; the Constitution is supreme
Constitution	Unwritten, flexible	Written, rigid
Can the centre abolish the units' powers by ordinary law?	Yes, in law	No
Judiciary	Cannot strike down an Act of Parliament	Supreme Court reviews laws of both levels
Citizenship	Single	Dual (national and state)
Upper House	House of Lords, not a house of the units	Senate, equal representation of states

Caution. Do not confuse *division of powers* (federalism, between levels of government) with *separation of powers* (presidential system, between organs). The USA has both; Britain has neither in the strict sense.

Britain as a Unitary State and the USA as a Federal State: key facts

Unitary state test: One sovereign centre
Units created by the centre
Centre can alter them by ordinary law
Example: Britain; If the lower body can be abolished by an ordinary Act, the state is unitary.
Federal state test: Written constitution
Division of powers
Rigid amendment
Independent judiciary as umpire
Example: the USA; Name at least four features with the USA example.
Features of Britain as a unitary state: Sovereign Parliament
One central government
Devolution by ordinary Acts
Unwritten and flexible constitution
Single citizenship; Devolution to Scotland, Wales and Northern Ireland does not make Britain federal.
Features of the USA as a federal state: Supremacy of the Constitution
Powers divided by Article I and the Tenth Amendment
Rigid amendment
Supreme Court as umpire
Equal state representation in the Senate
Dual citizenship; Residuary powers lie with the states.

How to answer Britain as a Unitary State and the USA as a Federal State questions

Questions on this topic ask for meaning and features of one country (4 marks), or a comparison on stated points (4 to 6 marks).

1Define the type of state in one line.
2Give features in numbered points, each with a Britain or USA example.
3For comparison, use a table or paired sentences on the same basis (source of power, constitution, judiciary, citizenship).
4Do not write about federal features while answering on Britain.
5Close with one line linking the feature to the type, for example that devolved bodies exist by an Act and can in law be changed.

Britain as a Unitary State and the USA as a Federal State in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Branch offices versus partner firms

Suppose a company has one head office that opens branch offices, sets their powers by a circular and can close any of them. Suppose another arrangement is a partnership deed that fixes what each partner controls, and no partner can alter it alone.

Which arrangement resembles a unitary state and which a federal state?

Try it first, then show the solutionSolution

The branch offices exist because the head office created them and can change their powers by its own order.
The partnership deed fixes each partner's share and cannot be changed by one partner alone.

Answer: The head office with branches resembles a unitary state; the partnership deed resembles a federal state.

Memory hook: Circular from the centre = unitary; deed that binds both = federal.

Delegated power is not protected power

Imagine a school principal lets the student council run the library fund, but a written school rule says the principal may change this at any time.

Does the student council hold federal-style power? Relate this to devolution in Britain.

Try it first, then show the solutionSolution

The council's power was given by the principal, not guaranteed by a document above both.
The principal can take it back by a simple order.
Devolved bodies in Britain are in the same position in law, since they rest on ordinary Acts.

Answer: No, it is delegated power, like British devolution; federal power would be protected by a constitution above both sides.

Memory hook: Devolution = lent; federation = owned.

Tricks to remember Britain as a Unitary State and the USA as a Federal State

Short memory aids. Say each one aloud once, then use it on a question the same day.

Federal features: W-D-R-J-S
Written constitution, Division of powers, Rigid amendment, Judiciary as umpire, Supremacy of the Constitution.
Use it when: Listing the features of the USA.
Unitary Britain: S-O-D-U
Sovereign Parliament, One government, Devolution by Act, Unwritten constitution.
Use it when: Listing the features of Britain.
Residuary powers
USA: the Tenth Amendment gives leftover powers to the states.
Use it when: Avoiding the mistake of giving them to the Union.

Britain as a Unitary State and the USA as a Federal State: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Identify the type · 1 mark · MCQBoard level

Which one of the following is a feature of Britain as a unitary state?
(a) Rigid written constitution
(b) Supremacy of Parliament
(c) Equal representation of units in the upper house
(d) Dual citizenship

Try it first, then show the solutionSolution

Parliamentary sovereignty marks a unitary state; (a), (c) and (d) describe federal features, here the USA (1 mark).

Answer: (b) Supremacy of Parliament

Example 2: Meaning · 2 marks · Very short answerBoard level

Distinguish a unitary state from a federal state in terms of the source of power of the units. (2 marks)

Try it first, then show the solutionSolution

Unitary: units get power from the central government and may lose it (1 mark).
Federal: units get power from the constitution, so the centre cannot take it away by ordinary law (1 mark).

Answer: In a unitary state such as Britain, local and devolved bodies hold only the powers that Parliament gives them, and Parliament may change them by ordinary law. In a federal state such as the USA, the powers of the states come from the Constitution itself, so the Union cannot reduce them by an ordinary law.

Example 3: Assertion and reason · 1 mark · Assertion-reasonHarder board level

Assertion (A): Britain remains a unitary state although Scotland has its own Parliament.
Reason (R): The powers of the Scottish Parliament rest on an Act of the UK Parliament, which can in law amend or repeal it.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Try it first, then show the solutionSolution

A is true. R is true and it is exactly why devolution does not make Britain federal (1 mark).

Answer: (a) Both A and R are true and R is the correct explanation of A.

Example 4: Features of the USA · 4 marks · Short answerHarder board level

Explain four features that make the USA a federal state. (4 marks)

Try it first, then show the solutionSolution

Supreme written Constitution and division of powers (1 mark).
Rigid amendment (1 mark).
Supreme Court as umpire (1 mark).
Equal representation of states in the Senate or dual citizenship (1 mark).

Answer: (i) The USA has a written Constitution that is the supreme law; it lists the powers of the national government and, by the Tenth Amendment, reserves the remaining powers to the states. (ii) It is rigid: an amendment needs a two-thirds proposal in Congress or by a convention and ratification by three-fourths of the states, so neither level can alter the division alone. (iii) The Supreme Court acts as umpire and can declare a law of either the Union or a state void if it violates the Constitution. (iv) Every state, large or small, has two Senators, so the states share in national law-making, and a person holds both national and state citizenship.

Example 5: Comparison · 6 marks · Long answerHOTS / competency

Explain how the way lower levels of government get their authority makes Britain unitary and the USA federal, and support your answer with three further contrasts between the two. (6 marks)

Try it first, then show the solutionSolution

Source of power (1.5 marks).
Constitution (1.5 marks).
Judiciary (1.5 marks).
Citizenship (1.5 marks).

Answer: Source of power: in Britain the sovereign Parliament is the source of all power, and devolved and local bodies hold what Acts give them; in the USA the Constitution divides power between the Union and the fifty states and each level is protected from the other.

Constitution: Britain's constitution is unwritten and flexible, so Parliament can change it by ordinary law; the American Constitution is written and rigid, changed only through the procedure in Article V.

Judiciary: British courts cannot strike down an Act of Parliament; the American Supreme Court interprets the Constitution and can invalidate laws of Congress or the states that go against it, which makes it the umpire between levels.

Citizenship: Britain has a single citizenship; the USA has dual citizenship, national and state.

Where students lose marks in Britain as a Unitary State and the USA as a Federal State

The slips examiners see most often, and what to write instead.

Mistake: Calling Britain federal because of devolution
Not seeing that devolved powers rest on ordinary Acts.
Wrong working
Scotland has its own Parliament, so Britain is federal.
Right working
Devolution rests on an Act that Parliament can change; sovereignty stays with Parliament, so Britain is unitary.
Do this: Always say who can take the power back.
Usually costs: 1 to 2 marks.
Mistake: Giving residuary powers to the Union for the USA
Carrying over the Indian arrangement.
Wrong working
In the USA the remaining powers are with the Union government.
Right working
Tenth Amendment: powers not given to the Union or denied to the states are reserved to the states or the people.
Do this: Link the USA to the Tenth Amendment.
Usually costs: 1 mark.
Mistake: Mixing division and separation of powers
Both words sound alike.
Wrong working
Federalism means three organs are separate.
Right working
Federalism is division of powers between levels; separation of powers is between legislature, executive and judiciary.
Do this: Ask "between whom?"
Usually costs: 1 mark.

Exam tips

Write the type of state, then numbered features, each tied to the named country.
For a comparison, use the same bases for both countries, in a table or paired lines.
Use the correct word: Parliament for Britain, Congress for the USA.
In a comparison, state that British courts cannot invalidate an Act of Parliament while the American Supreme Court can invalidate a law that breaks the Constitution.

Practice questions on Britain as a Unitary State and the USA as a Federal State

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
Under which amendment are powers not given to the Union reserved to the states in the USA?
(a) First Amendment
(b) Tenth Amendment
(c) Fourteenth Amendment
(d) Twenty-second Amendment
Hint
Think of residuary powers.
Answer
(b) Tenth Amendment.
Q2 · 2 marks · Very short answerHarder board level
State two merits of the unitary form of government as seen in Britain. (2 marks)
Hint
Speed and uniformity.
Answer
(i) Decisions can be taken quickly and enforced uniformly because there is one centre of authority. (ii) There is no dispute over the division of powers between levels, and administration costs less because there is no duplicate set of governments.
Q3 · 1 mark · Assertion-reasonHarder board level
Assertion (A): The Supreme Court of the USA is called the umpire of the federal system.
Reason (R): It can decide disputes between the Union and the states and between states.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Hint
The reason describes the umpire role.
Answer
(a) Both A and R are true and R is the correct explanation of A.
Q4 · 4 marks · Short answerHarder board level
Explain why devolution of powers to Scotland, Wales and Northern Ireland has not changed Britain into a federal state. (4 marks)
Hint
Source and protection of the powers.
Answer
(i) The devolved bodies were created by ordinary Acts of the UK Parliament in 1998 (the Scotland Act, the Government of Wales Act and the Northern Ireland Act). (ii) Parliament remains sovereign and can in law amend or repeal those Acts, so the powers are lent, not constitutionally guaranteed. (iii) There is no written constitution dividing power between two levels and no court that can strike down an Act of Parliament to protect the devolved bodies. (iv) In a federation the units hold protected powers that the centre cannot remove by ordinary law; this protection is missing, so Britain stays unitary even though devolution has widened local self-government in practice.
Q5 · 6 marks · Long answerHOTS / competency
Suppose a classmate argues, "The USA is not truly federal because Congress can pass laws that bind every state." Reply using the features of federalism. (6 marks)
Hint
Supremacy within a sphere; amendment; Senate; courts.
Answer
The argument mixes up national supremacy in its own field with the absence of federalism. In a federation each level is supreme in its own sphere. Congress may legislate only on matters the Constitution gives it, such as interstate trade, taxation for the Union, and war; the Tenth Amendment reserves other powers to the states, which have their own constitutions, legislatures, governors and courts. The Supremacy Clause makes the Constitution, and valid federal law made under it, binding on state law; that is a rule of the federal arrangement, not a negation of it. Congress cannot alter the division by an ordinary law: any change needs an amendment proposed by two-thirds of Congress (or a convention called on the application of two-thirds of the state legislatures) and ratified by three-fourths of the states. The Supreme Court can strike down a federal law that goes beyond the Constitution. The states are represented equally in the Senate, so they share in national law-making. Therefore the USA remains a federal state, though the balance between the levels has been debated at different times.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Where does sovereignty rest in Britain?Show answer
With the Parliament.
2.What reserves residuary powers to the states in the USA?Show answer
The Tenth Amendment.
3.How many Senators does each American state have?Show answer
Two.
4.Which Article of the American Constitution contains the supremacy clause?Show answer
Article VI.
5.Is the British constitution rigid or flexible?Show answer
Flexible.

Britain as a Unitary State and the USA as a Federal State: frequently asked questions

Is the United Kingdom a federation?

No. It is a unitary state because the sovereign Parliament created the devolved bodies by ordinary Acts and can in law change them.

Why is the USA called a federal state?

Because its written Constitution divides power between the Union and fifty states, is rigid, and is protected by an independent Supreme Court.

What is the main difference between the two in one line?

In Britain the centre gives power to the units; in the USA the Constitution gives power to both levels.

Does a federal state need a written constitution?

The syllabus treats a written, rigid constitution as an essential feature, because the division of powers must be fixed in a document above both governments.