The Importance of Judicial Dissent in Constitutional Interpretation

Louis O'Carroll


Before 2013, the Irish Constitution prescribed a ‘single-judgment rule’ for any case involving the constitutional validity of a post-1937 law. This was abolished with the enactment of the 33rd Amendment. However, a single-judgment rule still applies today in respect of laws referred by the President to the Supreme Court for constitutional scrutiny under Article 26. The main architect of the single-judgment rule was Eamon de Valera, whose ideal constitution was one which was ‘unambiguous’.[1]

In this piece I seek to establish the value of dissenting judgments in constitutional discourse. In Part I, I distinguish dissents from majority judgments, arguing that dissents, unburdened by the practical exigencies of majority judgments, lend themselves to rhetorical persuasion. In Part II, I challenge the idea that a constitution can ever be unambiguous and argue that, as a result, a single-judgment rule is inappropriate in any case involving constitutional interpretation. Finally, in Part III I argue that the rhetorical function of dissents expounded in Part I renders them a valuable resource for judges seeking to navigate the decidedly ambiguous issues inherent in constitutional interpretation.


Part I - Distinguishing Dissents from Majority Judgments

The character of a dissent is entirely different to that of a majority judgment. While a majority judgment enjoys the force of law, this carries with it a significant amount of responsibility. A judge deciding for the majority must take into consideration the consequences his decision will bring to bear on the parties to the case, and in the event that he is setting a binding precedent, society in general. A necessary corollary of this is that the greater the impact a decision has, the more it and its reasoning will be scrutinised by those affected. Scrutiny is a potent check on judges, especially in light of the fact that the judiciary’s capital is intellectual and reputational, and can be eroded by persistent criticism.[2]

On the other hand, the non-binding nature  of dissents means that a dissenting judge is not as constrained by these considerations. The only requirement by which they must abide is that the dissent does not agree with the majority. The freedom which this affords the judge enables a dissent to perform a number of functions beyond the immediate purpose of a majority judgment: to settle a legal dispute between parties. For instance, in framing its disagreement with the majority, a dissent can signal to a specific group in society, for example by making an impassioned plea to the legislature to consider some reform. Alternatively, it can serve as an invitation for a prospective ‘perfect’ plaintiff to bring a case so that a particular issue can be addressed.[3]

What is notable about these functions is that they are characterised more by rhetorical persuasion than they are by legal reasoning seeking to justify a binding decision. That is not to say that dissents require no use of legal reasoning; the crucial distinction, I would argue, is that in dissents, legal reasoning is only necessary insofar as it aids with the rhetorical persuasion in which the judge is engaging. While majority judgments can engage in rhetorical persuasion, their efficacy in doing so is limited by the considerations, outlined above, of the consequences of their decisions and the higher scrutiny to which they are subject. [4]

I later argue that this rhetoric allowed in dissenting judgments is most valuable in cases which are inextricably concerned with contested concepts and issues not solvable by recourse to logic. An example of an area of law fraught with such ambiguity is constitutional interpretation, to which I now turn.


Part II - The Single-Judgment Rule and the Pursuit of an ‘Unambiguous’ Constitution

Constitutions are aspirational documents. The Irish Constitution in its Preamble sets out its goals, for example that ‘true social order [be] attained.’ While the merit of this lofty goal can scarcely be challenged, the means by which it is achieved most certainly can be. Say, for example, a court is called on to decide whether or not the implementation of an emergency rent-freeze would work towards establishing a ‘true social order’. Whatever the court decides has implications for the interpretation of the constitutional provisions at issue. How, then, should the court approach this issue?

The intuitive approach I would take, informed by realist thinking, is to say that there is no objectively right answer to this question. Certainly, I might prefer one approach over another, or disagree vehemently with a certain approach. However, the reality is that a court could conceivably choose any approach from what Ferejohn and Kramer call the ‘recognisable domain of permissible legal arguments’; those being arguments which are, as a matter of fact, accepted as being part of existing legal discourse.[5]

A single-judgment rule for constitutional adjudication (perhaps understandably) seeks to ignore the reality of this inherent ambiguity. By confining the court’s decision to a single judgment, the rule forces a court to pretend that the above-mentioned domain of permissible arguments doesn’t exist. At first blush, it is possible to consider the benefits such a rule may have for the principle of legal certainty and clarity. However, does this still stand when this certainty and clarity is based on a fiction? In my opinion, it is better to acknowledge the pluralism necessitated by the aspirational nature of constitutions, and to encourage debate of these intractable issues.

For this reason, I disagree with the contention that the best constitution is an unambiguous one and thus conclude that the single-judgment rule for cases involving constitutional interpretation is improper. Such a rule ignores the indeterminacy inherent in interpreting constitutional text. Further, it fails to allow for the unique role which dissents play in this category of ambiguous cases. I will now examine this role as applied in cases of constitutional interpretation.


Part III - The Value of Dissent in Constitutional Interpretation

It has been established both that dissents lend themselves to rhetorical persuasion, and that constitutional interpretation is rife with ambiguity. I will now examine how these factors interact to fashion a unique role for dissenting judgments to play in cases of constitutional interpretation.

Constitutional interpretation often risks encroaching on the competence of the other branches of government.[6] Aileen Kavanagh argues that judges ought to take into account both institutional and substantive considerations into account when adjudicating on human rights issues; institutional in this context meaning a judge considering his proper role vis-á-vis the other branches of government.[7] She concludes that there exist some situations where the institutional reasons for exercising restraint outweigh the substantive merits of a claim. I find this to be an unpalatable if unavoidable prospect, but one which may be tempered by the use of dissents.

As highlighted earlier, dissenting judges are unconstrained by the external consequences of their judgments precisely because their judgments have no external consequences. The meaning of ‘external consequence’ in the context of constitutional interpretation can be extended to include the impact on relations between the judiciary and the other branches caused by an activist decision. As such, a dissenting judge need not take into account these institutional limitations in their reasoning and is free to offer a dissent focusing solely on the substantive merits of the issue at hand. This allows the judge to go beyond his institutional competence—albeit in a non-binding way—and offer to the public an unconstrained differing opinion on the proper interpretation of the constitutional provisions at issue in a given case.

This unconstrained second opinion is particularly valuable in light of the ambiguity inherent in constitutional interpretation. When a court employs reasoning from the ‘domain of permissible arguments’ elucidated above in interpreting a constitution, that reasoning should be scrutinised. However, reasoning drawn from this domain cannot simply be dismissed outright; as it has broadly been accepted as at least existing in legal discourse, all that can be done in attempting to persuade a reader that a different reasoning is to be preferred. This is where the freedom to engage in rhetorical persuasion associated with dissenting judgments is most valuable. A dissenting judge, in trying to persuade a reader that his approach is the proper one, invites a critical appraisal of the majority’s reasoning. Whether or not he is successful in convincing the reader, the dissent highlights the existence of other possible approaches to an issue. This, I argue, reflects the reality of constitutional interpretation.



In this piece I have argued that dissents play a valuable role in constitutional interpretation. The phenomenon of dissenting judgments as a prophetic ‘voice of the future’ reflects the fact that they are unconstrained by the considerations taken into account by majority judgments. In order for dissents to be able to play this role, they must be allowed. As such, I would call for the wholesale removal of the single-judgment rule from Irish constitutional law.


[1] Nora Ní Loinsigh, ‘Judicial Dissent in Ireland: Theory, Practice and the Constraints of the Single Opinion Rule’ (2014) 51(1) The Irish Jurist 123, 137.

[2] John Ferejohn and Larry Kramer, ‘Independent Judges, Dependent Judiciary: Institutionalizing Judicial Restraint’ (2002) 77(4) NYU Law Review 962, 977.

[3] A recent, poignant example of such signalling can be seen in the dissent of Justice Kagan of the US Supreme Court in Rucho v Common Cause (2019) 139 S. Ct. 2484.

[4] A majority judgment may well make obiter comments as to future, hypothetical cases which may go a different way in different circumstances. However, I argue that such comments are to be read as a refinement of the majority reasoning, as opposed to a novel argument in its own right. As such, they are still linked by association to the practical constraints outlined above.

[5] Ferejohn and Kramer (n 2), 972.

[6] An example of this can be seen in the seminal case of TD v Minister for Education [2001] IESC 101, in which the Supreme Court held that the separation of powers as established in the Irish constitutional order precluded the Court from making an order requiring the Government to construct accommodation for vulnerable children.

[7] Aileen Kavanagh, ‘Judicial Restraint in the Pursuit of Justice’ (2010) 60(1) The University of Toronto Law Journal 23, 27-29.


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