The three branches in the text
One simple example: the Oireachtas passes a law, the Government administers it, and a court can decide a legal challenge to how it applies.
The Oireachtas makes law
- TDs and Senators debate Bills
- The Dáil decides confidence and public spending
- The President signs a Bill after passage
The courts decide cases
- Judges interpret and apply the law
- Courts can review whether a law or decision is constitutional
- Government and parliament cannot direct a judge's decision
| Branch | Who | Constitutional basis |
|---|---|---|
| Legislative | The Oireachtas: President, Dáil and Seanad | Article 15.2.1 vests the sole and exclusive power of making laws in the Oireachtas. |
| Executive | The Government, led by the Taoiseach | Article 28.2 says executive power is exercised by or on the authority of the Government. |
| Judicial | Judges in courts established by law | Article 34 and Article 35, which guarantee judicial independence. |
On the course: Leaving Cert Politics and Society topic 2 asks for the executive, the legislature, and the judiciary side by side. CSPE strand 3 asks for the same three, in less detail.
Article 6 ties the three together: all powers of government, legislative, executive and judicial, derive from the people and are exercised only by or on the authority of the organs of State set up by the Constitution.
You can watch the split in one week of the 34th Dáil. On 23 January 2025 the Dáil, the legislature, nominated Micheál Martin as Taoiseach, the head of the executive. The President appointed him. The courts were not in that vote. If a later Act conflicts with the Constitution, a court can say so. The Dáil cannot sit as that court, and the Taoiseach cannot either.
Why Ireland has fusion, not strict separation
In a presidential system like the United States, members of the executive cannot sit in the legislature. Ireland follows the Westminster tradition instead. Under Article 28.7, the Taoiseach, Tánaiste and Minister for Finance must be members of the Dáil, and every other Minister must be a TD or Senator, with no more than two from the Seanad.
Under Article 28.4.1 the Government is responsible to Dáil Éireann. If the Taoiseach loses the support of a majority in the Dáil, Article 28.10 requires resignation unless the President dissolves the Dáil on the Taoiseach's advice. That is why a confidence vote matters so much.Read how Dáil confidence motions work.
The practical result is that a Government with a stable majority usually controls the Dáil agenda and passes its legislation. Political scientists often describe this as executive dominance. It is a strong theme for essays: the formal rules suggest parliament controls government, while day-to-day practice often runs the other way.
Checks and balances in practice
| Check | Who uses it | Example |
|---|---|---|
| Confidence and no-confidence motions | Dáil on Government | A Government that loses Dáil support must resign or seek a dissolution. |
| Parliamentary questions and committees | TDs and Senators on Ministers | Written and oral questions, committee hearings, the Public Accounts Committee. |
| Judicial review | Courts on the Oireachtas and Government | A law or decision can be declared invalid if it breaches the Constitution. |
| Article 26 reference | President on the Oireachtas | A Bill can be referred to the Supreme Court before it is signed. |
| Appointment and removal of judges | Government and Oireachtas on courts | Judges are appointed by the President on Government advice and removed only by resolutions of both Houses for stated misbehaviour or incapacity. |
| Referendums | The people on everyone | Only the people can change the Constitution itself. |
Cases that shaped the boundaries
Useful authorities for law and PPE students. Read the judgments themselves before relying on them.
- Buckley v Attorney General [1950] IR 67
- The Sinn Féin Funds case. The Oireachtas could not pass a law directing the outcome of litigation already before the courts.
- Cityview Press v An Chomhairle Oiliúna [1980] IR 381
- Set the principles and policies test: the Oireachtas may delegate detailed rule-making, but the parent Act must contain the principles and policies itself.
- Crotty v An Taoiseach [1987] IR 713
- The Government's foreign policy powers were limited by the Constitution, so ratifying the Single European Act required a referendum.
- TD v Minister for Education [2001] 4 IR 259
- The Supreme Court warned that courts should not make orders directing the executive on how to carry out policy, citing the separation of powers.
Questions to test yourself
- Why must the Minister for Finance be a TD rather than a Senator?
- What happens under Article 28.10 if the Taoiseach loses Dáil support?
- Is the Irish system closer to the UK or the US on separation of powers? Why?
- When should courts decline to tell the Government how to spend money?
- Does executive dominance make the Dáil less important, or just important in different ways?