Authored By: Jake Nolan
TU Dublin
Thesis Statement
The Supreme Court’s decision in DPP v JC,1 while motivated by legitimate concerns about the rigidity of the absolute exclusionary rule established in DPP v Kenny,2 fundamentally compromises the vindication of constitutional rights by permitting the admission of unconstitutionally obtained evidence where a Garda acted in good faith. In doing so, the majority subordinated the protective function of the exclusionary rule to prosecutorial utility, producing a framework that is doctrinally incoherent and constitutionally inadequate.
Part I – Introduction
For decades, the Irish exclusionary rule operated as an uncompromising safeguard: evidence obtained through a deliberate and conscious violation of constitutional rights was inadmissible, save in extraordinary circumstances. That position, cemented in DPP v Kenny,3 reflected a judicial commitment to the vindication of constitutional rights as a value in itself, not merely as a remedy of last resort. In 2017, a four-to-three majority of the Supreme Court dismantled that foundation.
In DPP v JC,4 the majority, led by Clarke J, replaced the near-absolute Kenny rule with a modified test under which unconstitutionally obtained evidence may be admitted where the prosecution establishes that the relevant breach was not deliberate or conscious — meaning the Garda genuinely, if mistakenly, believed they were acting lawfully. This good faith exception was presented as a principled recalibration. It was not.
This article argues that the JC5 framework, rather than refining the exclusionary rule, fundamentally distorts it by shifting focus from the rights of the accused to the subjective state of mind of the investigating officer, thereby rendering constitutional protection contingent on the very conduct it is designed to police. The article proceeds by examining the doctrinal foundations of the Kenny rule, analysing the majority’s reasoning in JC,6 and demonstrating why the good faith exception fails as a matter of constitutional principle.
Part II – Main Body
The Constitutional Foundation of the Irish Exclusionary Rule
The Irish exclusionary rule is rooted in the Constitution, rather than statute. It derives from the State’s obligation under Article 40.3,7 which is in place to “defend and vindicate the personal rights of the citizen,” in addition to Article 38.1,8 which guarantees the right to a fair trial. Due to its constitutional grounding, modification by the courts is not a mere procedural adjustment, but rather a statement about the nature and enforceability of the doctrines themselves. The foundation of the rule lies in the case of O’Brien,9 where Walsh J held that evidence obtained by a deliberate and conscious violation of constitutional rights ought ordinarily to be excluded, though he preserved a limited judicial discretion to admit evidence in exceptional circumstances. That discretion was the subject of significant controversy, and in Kenny,10 the Supreme Court moved to eradicate it entirely. The ultimate basis for the Kenny11 rule was that constitutional rules required a reliable remedy, and a discretionary one was in fact no remedy at all.
From Kenny to JC: The Dismantling of Absolute Protection
In order to understand the significance of JC,12 it is imperative that Kenny‘s13 “deliberate and conscious” violation is understood precisely. The phrase did not require that the Garda knew they were breaching the Constitution. It required only that the act giving rise to the violation was itself deliberate. A Garda who intentionally entered a premises under a warrant later found to be unconstitutional committed a deliberate and conscious violation under Kenny,14 regardless of their honest belief in the warrant’s validity. The rule operated objectively.
The factual matrix of JC placed that objective standard under acute pressure. In Damache v DPP,15 the Supreme Court declared section 29(1)16 unconstitutional, on the basis that it permitted a Garda superintendent, rather than a neutral and independent authority, to issue search warrants in certain circumstances. The search at issue in JC17 had been conducted under precisely such a warrant, executed in good faith by a Garda who had no reason to know of the constitutional infirmity that Damache18 would later expose.
The majority in JC,19 per Clarke J, held that the Kenny20 rule required recalibration. Where the prosecution could demonstrate that the relevant breach was not deliberate or conscious — in the sense that the officer genuinely believed they were acting lawfully — the evidence was not subject to automatic exclusion. The court retained a residual discretion to exclude, but the foundational presumption of exclusion was displaced. In practical terms, the JC21 framework requires the trial judge to assess the officer’s subjective belief as the primary determinant of admissibility.
Good Faith as a Constitutional Defect, Not a Constitutional Solution
The majority in JC22 presented the good faith exception as a proportionate response to the rigidity of Kenny,23 and the concern motivating it is not without force. It is a legitimate question whether it is just to suppress reliable evidence of serious criminality because an officer, acting in entirely honest ignorance, relied upon a warrant that would later be declared unconstitutional. However, a rule motivated by concern for prosecutorial convenience cannot derive its validity from constitutional principle, and on examination, the JC24 framework fails that test.
The most fundamental objection is inherently structural. Constitutional rights in Ireland are held by citizens against the State and its agents. The function of the exclusionary rule, as articulated in both O’Brien25 and Kenny,26 is to vindicate those rights by ensuring that the courts do not become instruments for the exploitation of unconstitutionally obtained evidence. Under the JC27 framework, however, the central inquiry is no longer whether a constitutional right was violated, but whether the State’s agent was aware of the violation. The rights-holder’s position becomes secondary to the mental state of the person constitutionally bound to respect the right. A right whose enforceability depends upon the knowledge of the violator is, in any meaningful sense, diminished.
The dissenting judges in JC28 identified a further doctrinal incoherence. The Kenny29 rule had been adopted precisely because the discretionary framework in O’Brien30 had proved unpredictable and unduly deferential to prosecution interests. The JC31 majority replaced a near-absolute rule with a test that reintroduces precisely that discretion, now structured around the officer’s subjective state of mind rather than any fixed legal criterion. In doing so, the majority reproduced the instability that Kenny32 had been designed to cure, without acknowledging that it had done so.
The deeper constitutional objection is this: the Irish exclusionary rule was never conceived as a deterrent mechanism designed to discipline Garda behaviour. It was conceived as a vindicatory one, designed to protect the constitutional rights of the individual as against the State. Those two foundations demand different responses to the problem of innocent error. A deterrence-based rule might reasonably yield where there is no conduct to deter. A vindicatory rule cannot yield on the same logic, because the violation of the right occurs regardless of the officer’s intention, and the accused’s entitlement to its vindication does not diminish because the State’s agent acted in good faith. The JC33 framework conflates these two distinct rationales, and in doing so imports a logic that is constitutionally foreign to the Irish rule. If the purpose of exclusion is to vindicate the rights of the accused, that purpose is not served by a test that asks, first and foremost, whether the Garda meant well.
Part III – Conclusion
DPP v JC34 represents a significant and, it is submitted, constitutionally deficient departure from the principles that underpinned the Irish exclusionary rule. By replacing the near-absolute protection established in Kenny35 with a framework centred on the subjective good faith of the investigating officer, the majority shifted the rule’s focus from the vindication of the accused’s constitutional rights to the culpability of the State’s agent. That shift is not a refinement. It is a reversal of the rule’s foundational logic.
The exclusionary rule exists because constitutional rights require reliable remedies. A remedy that dissolves upon proof of honest mistake is not reliable; it is contingent. The JC36 framework does not balance the rights of the accused against the interests of the prosecution. It subordinates the former to the latter under the guise of proportionality. Until that distinction is confronted directly, the constitutional guarantee that the rule was designed to enforce will remain, in cases of genuine but mistaken violation, effectively unenforceable.
Bibliography
- Bunreacht na hÉireann 1937.
- Damache v DPP [2012] IESC 11.
- DPP v JC [2017] IESC 1.
- DPP v Kenny [1990] 2 IR 110.
- Offences Against the State Act 1939.
- The People (AG) v O’Brien [1965] IR 142.
Footnote(S):
1 [2017] IESC 1.
2 [1990] 2 IR 110.
3 Ibid.
4 JC (n1).
5 Ibid.
6 Ibid.
7 Bunreacht na hÉireann 1937.
8 Bunreacht na hÉireann 1937.
9 The People (AG) v O’Brien [1965] IR 142.
10 Kenny (n2).
11 Ibid.
12 JC (n1).
13 Kenny (n2).
14 Ibid.
15 [2012] IESC 11.
16 Offences Against the State Act 1939.
17 JC (n1).
18 Damache (n15).
19 JC (n1).
20 Kenny (n2).
21 JC (n1).
22 Ibid.
23 Kenny (n2).
24 JC (n1).
25 O’Brien (n9).
26 Kenny (n2).
27 JC (n1).
28 Ibid.
29 Kenny (n2).
30 O’Brien (n9).
31 JC (n1).
32 Kenny (n2).
33 JC (n1).
34 Ibid.
35 Kenny (n2).
36 JC (n1).
