Double Standards of Rationality by Marcus

Double Standards of Rationality by Marcus Teo*

The review of decisions on grounds of irrationality (rationality review) is central to modern administrative law. Thus, Singapore’s courts have affirmed a general standard of rationality review, applicable regardless of a decision-maker’s office or the field he purports to have an expertise in. However, a special standard of rationality review, rendering decisions entirely non-justiciable on grounds of rationality precisely because of a decision-maker’s office and/or his expertise, has in recent years been applied to exercises of the prosecutorial power. This comment traces the evolution of these two standards of rationality in Singaporean jurisprudence, and highlights the tensions that arise between them.

Since the English Court of Appeal’s hallowed statement of the law in Associated Provincial Picture Houses v Wednesbury Corporation, it has been trite that administrative decisions may be subject to judicial review on grounds of irrationality, when they are “so absurd that no sensible person” would countenance them1 (rationality review). In recent years, Singapore’s courts seem to have developed a clear preference for the stance that administrative decisions should ordinarily always be subject to rationality review, regardless of the relevant subject-matter at issue.

However, courts also appear to have developed a divergent special standard of judicial review, which applies only to exercises of the prosecutorial power. Specifically, the courts appear to have in recent years considered the prosecutorial power to be immune from rationality review. This comment traces the evolution of these two standards of judicial review in recent years, and highlights the tensions that arise between them.

The Ordinary Standard: Administrative Decisions and Rationality

A great challenge that courts face when asserting the power of judicial review over administrative decisions is their lack of subject-matter expertise in the relevant field. Experts only in law cannot purport to comprehend the nuances of non-legal expertise, and thus understandably hesitate to substitute their reasoning for it. At one level, this deficit in subject-matter expertise justifies the ordinary test for rationality review. However, on a higher level, this deficit apparently manifests also in the exceptional doctrine of non-justiciability, where courts would identify “provinces of executive decision-making that are, and should be, immune from judicial review”.2 Such a decision’s propriety arguably cannot be subject to rationality review at all.3

Nevertheless, Singapore’s courts appear to have gradually eroded the edifice of non-justiciability in recent years. In Lee Hsien Loong v Review Publishing (Review Publishing),4 however, Sundaresh Menon JC (as he then was) doubted that an assertion of subject-matter expertise could ever render an entire field of executive decision-making non-justiciable. Noting generally that “[j]usticiability depends, not on the source of the decision-making power, but on the subject matter that is in question”, he observed that “[t]here may…be situations where the courts are able to isolate a pure question of law from what may generally appear be a non-justiciable area.5 Thus, he suggested that specific decisions impugned by parties may be justiciable (and thus subject to rationality review), even if courts lack the expertise to comprehend the field of knowledge relevant to that decision-making exercise.

Subsequently, in Tan Seet Eng v Attorney-General (Tan Seet Eng),6 the Court of Appeal went further by endorsing the justiciability of all decisions, regardless of the relevant fields of expertise they belong to. There, the Court maintained that while “[t]he judge…must resist a temptation to turn sociologist, economist, and politician … [i]f any executive or administrative authority … fail[s] to observe or to apply the law, it is the responsibility of the Judiciary … to declare and to refuse to give legal effect to [its acts]”.7 Thus, the Court held that while “the more remote the subject matter of a decision from ordinary judicial experience, the more hesitant the court must necessarily be in holding a decision to be irrational”, the notion that executive decision-making “may not be scrutinised by the court at all” should nevertheless be indefensible.8 In essence, the Court of Appeal confirmed that a lack of understanding of the field the decision-maker is an expert in should not immunise any specific decision from rationality review; in essence, “[j]udges are entrusted with the task of ensuring that any exercise of state power is done within legal limits.”9

Thus, from Review Publishing to Tan Seet Eng, the courts developed an uncompromising and generally applicable standard of judicial review over administrative decisions that includes rationality review, which ordinarily applies to each individual act of administrative decision-making – the court’s subject-matter expertise (or lack thereof) in the relevant field notwithstanding.

The Special Standard: The Prosecutorial Power and Expertise

However, not eight months after Review Publishing, a divergent standard of judicial review had begun its gestation – a special standard, involving only the prosecutorial power, which may broadly be understood as including the constitutional discretion of the Public Prosecutor (PP) to either institute, maintain or discontinue criminal proceedings,10 and statutory discretions given to the PP in the discharge of specific functions.

In Law Society of Singapore v Tan Guat Neo Phyllis (Phyllis Tan), the Court of Three Judges laid down the first thorough statement of the prosecutorial power’s legal limits. It held firmly that prosecutorial discretion would be subject to the limit of illegality, noting that exercising the discretion in “bad faith for an extraneous purpose” would be precluded.11 However, the Court omitted to make a similar statement on grounds of irrationality.12

The point arose in Phyllis Tan through a line of reasoning undertaken by the Court of Three Judges that went as follows: because the PP is uniquely qualified to balance the relevant “public interests” in meting out criminal justice,13 no prosecution, not even one which might ordinarily be considered an “abuse of state power” 14 can be stayed; but the “prosecutorial power is not unfettered”, since the exercise of prosecutorial discretion may be quashed when in “bad faith for an extraneous purpose”. This context in which the Court’s pronouncements in Phyllis Tan were made emphasises how important its omission to state the availability of rationality review was. The prosecutorial power’s limits were not being enunciated in some tangential manner, where an apparent exclusion of a head of judicial review might be written off as an inadvertent omission. Instead, the Court of Three Judges took pains to explore those limits to justify why courts need not generally be concerned with policing the prosecutorial power’s exercise by staying prosecutions, and would have been expected to canvass fully the available grounds upon which the power’s exercise may be reviewed to defend its position.

There is thus good reason to believe that the Court of Three Judges intentionally omitted to state in Phyllis Tan that the exercise of prosecutorial power could be subject to rationality review. In particular, this would explain why the Court subsequently also stated that while it “has, in an appropriate case, the power within its own judicial sphere to declare a prosecution unconstitutional for breach of constitutional power”, “in the case of the prosecutorial power [this] would have to be a very exceptional case given that it is a constitutional power”.15 Thus, the Court of Three Judges in Phyllis Tan effectively held that the prosecutorial power may be exercised in any manner so long as it is bona fide for the prosecution of crime, even if the manner in which it is carried out seems irrational, since this is what the PP’s high office entails.

Nevertheless, no eyebrows were initially raised at Phyllis Tan’s special standard of review for the prosecutorial power. Indeed, in Ramalingam Ravinthran v Attorney-General (Ramalingam), the Court of Appeal appeared to assume that Phyllis Tan’s standard of “bad faith for an extraneous purpose” was equivalent to “[a]n arbitrary exercise of the prosecutorial power”, possibly contemplating rationality review, although little was said on the point.16 Yet, even in Ramalingam the Court of Appeal appeared to suggest there was something different about the prosecutorial power which warranted an easing up on the ordinary standards of judicial review – the Court held that the PP’s acts were relatively well-protected from judicial review by a presumption of constitutionality, which was stronger than that accorded to the acts of regular government officials,17 that existed simply by virtue of the PP’s “high office”.18

The disparity between the ordinary standard of judicial review and the special standard applicable to the prosecutorial power was made more readily apparent through amendments to the Misuse of Drugs Act (MDA)19 introduced in 2012. Through those amendments, a complex scheme was put in place, allowing the Public Prosecutor to certify when a trafficker/importer/exporter of controlled drugs who was merely a courier gave “substantive assistance” to the disruption of drug trafficking. Such a Certificate of Substantial Assistance would give courts the power to impose only a sentence of life imprisonment for trafficking/importing/exporting offences which would normally entail a mandatory death sentence.20 One of the central features of this scheme appeared to be the unassailability of the PP’s determination of whether the accused had indeed given such “substantive assistance”. Thus, a new section 33B(4) was also introduced into the MDA, which stated that that determination “shall be at the sole discretion of the [PP] and no action or proceeding shall lie against the [PP] in relation to any such determination unless it is proved to the court that the determination was done in bad faith or with malice” (emphasis added).

The use of such terms in MDA section 33B(4), evoking Phyllis Tan’s special standard of judicial review, was no mere coincidence – in justifying the breadth of 33B(4), the Minister of Law K Shanmugam argued:21

The Courts decide questions of guilt and culpability. As for the operational value of assistance provided by the accused, the Public Prosecutor is better placed to decide. The Public Prosecutor is independent and at the same time, works closely with law enforcement agencies and has a good understanding of operational concerns… whether a defendant’s cooperation has risen to the level of “substantial assistance” to the government is self-evidently a question that the prosecution is uniquely fit to resolve”.

Clearly, then, the central justifications for MDA section 33B(4) were similar to those for Phyllis Tan’s special standard of review. Yet, a tacit change in justification is evident here – while in Phyllis Tan and Ramalingam it was the PP’s office alone which seemed to justify a lack of rationality review, in the context of MDA section 33B(4) this office was considered relevant because of the field in which the PP is presumed to have expertise in by virtue of her office: the operational field of law enforcement.

The effect of MDA section 33B(4) exposing the disparity between the ordinary and special standards for judicial review proved controversial. In subsequent cases like Muhammad Ridzuan bin Mohd Ali v Attorney-General (Ridzuan)22 and Prabagaran a/l Srivijayan v PP, 23 courts beat a hasty retreat from Phyllis Tan’s discursive approach, shying away from considering the scope of the PP’s discretion to grant Certificates of Substantial Assistance in light of MDA section 33B(4). Only in Nagaenthran a/l K Dharmalingam v Attorney-General24 (Nagaenthran) was question properly canvassed and addressed.

The accused in Nagaenthran challenged the constitutionality of MDA section 33B(4) on three grounds: that it was contrary to Article 93 of the Constitution which vests the “judicial power” in the Supreme Court, that it was contrary to the separation of powers doctrine, and that it was repugnant to the “rule of law”.25 However, the former two grounds rely on a notion of the judiciary’s role in the separation of powers, which turns on the breadth of the “judicial power”, which itself turns on the breadth of “legality” (assessing the “legality” of actions being the only clear province of the judicial power).26 Thus, the only real question here was whether it would be contrary to Singapore’s understanding of the “rule of law”, that “all power has legal limits”,27 for the PP’s discretion to be challengeable only on grounds of “bad faith” or “malice”.

The High Court’s decision in Nagaenthran rejected the accused’s arguments, instead wholly endorsing Phyllis Tan’s special standard of judicial review for the prosecutorial power. Chan Seng Onn J first cited the Court of Appeal’s decision in SGB Starkstrom Pte Ltd v Commissioner for Labour for the principles relevant in determining the constitutionality of an ouster clause such as MDA section 33B(4), where it was held that both the separation of powers doctrine and the court’s lack of “institutional competence” on the subject-matter behind certain decisions limited the judiciary to reviewing only the “legality of administrative action”.28 However, while these statements in Starkstrom merely justified the applicability of the ordinary standard of judicial review which included rationality review,29 Chan J then went further in Nagaenthran by holding that the PP’s discretion in light of MDA section 33B(4) should also be immune from rationality review.30 In doing so, he cited the considerations provided by Minister Shanmugam concerning the PP’s office and the nature of the field in which the prosecutorial power operates.31 Crucially, Chan J also expounded clear reasons why such considerations should justify immunity from rationality review. Citing with approval an unaddressed submission made by the Attorney-General in Ridzuan, he noted that, given the “multitude of extra-legal factors” engaged by the prosecutorial power:32

What seemed like a minor difference, could, when viewed in light of operational considerations, turn out to be a determinative consideration in deciding whether an offender had rendered substantive assistance. The PP was best-placed to make this determination.

Essentially, then, Chan J’s position in Nagaenthran was a more fleshed-out version of the position taken by the Court of Three Judges in Phyllis Tan. His Honour’s argument went as follows. Since the prosecutorial power operates in a field so outside a reasonable man’s knowledge and comprehension, even decisions which seem “so absurd that no sensible person” would countenance them might be rational when seen through the lens of “operational concerns”. Hence, only the PP, whose office (apparently) entails that he has (as a matter of fact) a “good understanding” of such “operational concerns” in that field, should determine what “rationality” means in this paradigm. Thus, because of the PP’s apparent expertise in the field of law enforcement/criminal justice, the prosecutorial power should not be subject to rationality review.

Conclusion: Indefensible Double Standards?

The existence of a difference between the ordinary standard of judicial review (including rationality review) and the special standard for the prosecutorial power (excluding rationality review) is explained on the basis of the apparently unique nature of the field in which the prosecutorial power operates. However, to make such a proposition is simply to beg the question: what really is so special about the field of law enforcement/criminal justice? This is a question that warrants considering, in light of Jaclyn Neo’s caution, that the “superior expertise of the other branches of government … are invoked” as “sometimes more of an assertion of, rather than justification for, judicial non-intervention”.33

While full consideration of that proposition’s merits is beyond the scope of this comment,34 a few points may be made. It is interesting that from Phyllis Tan to Nagaenthran that courts appear to have abandoned the position that rationality review of the prosecutorial power’s exercise should be excluded simply because of the PP’s constitutional office. Such a position would clearly be contrary to the spirit of Menon JC’s statement in Review Publishing, that a decision’s subject-matter, rather than the source of the decision-making power, should be relevant in determining the ambit of judicial review.35

However, the courts’ recent justification, that rationality review should be excluded because no court can determine the very idea of rationality in the field of law/enforcement criminal justice, may be equally untenable. Indeed, if an entire field of knowledge could be said to exist in a different paradigm of rationality, the decisions of anyone who claims to be an expert in that field could have all her opinions insulated from rationality review simply by virtue of her self-proclaimed expertise. Further, a court would not be able to properly assess that self-proclaimed expert’s claim to such expertise precisely because of the very same assumption that that field of expertise lies entirely outside the court’s paradigm of rationality. Thusly, the decisions of the self-proclaimed expert would effectively be rendered a black box to the courts, and the justiciability of that field would effectively be contingent on the decision-maker’s identity (ie, the source of the decision-making power) rather than the decision’s subject-matter.

At the time of writing, a hearing by the Court of Appeal for the accused’s appeal in Nagaenthran had taken place.36 In a dramatic turn of events, the Court expressed an inclination to drastically read down the scope of MDA section 33B(4), opining it may merely be a provision granting the individual in the office of the PP and her agents a personal immunity from proceedings brought against them for any of their acts not carried out in bad faith or with malice.37 More important for our purposes, the Court seemed to disagree with the Attorney-General’s main argument in support of Chan J’s position in the High Court – that the PP’s discretion involves a non-justiciable field of expertise38 – and instead suggested that any attempt to insulate the PP’s decisions from “judicial review” would go to “the heart of judicial power”.39 Specifically, the Court found it “impossible to accept” the Attorney-General’s argument that it should be “powerless to act if [the PP] acted irrationally”.40 As the Court’s judgment on the appeal remains reserved, we can only speculate what its eventual position might be. Nevertheless, these comments by the Court suggest the possibility that it may collapse the strict distinction between the ordinary standard for judicial review over administrative decisions and the special standard in Phyllis Tan, with the former applying equally to exercises of the prosecutorial power.

I thank Benny Tan and Shuli Goh for their helpful comments, and Ariffin Sha and Joshua Chow for their perspectives. All views expressed and errors made herein are my own.

*”Double Standards of Rationality” was the feature article in the May 2019 of the Law Gazette.


  1. Associated Provincial Picture Houses v Wednesbury Corporation (1948) 1 KB 223 at 229.
  2. Lee Hsien Loong v Review Publishing Co Ltd (2007) 2 SLR(R) 453 at (95).
  3. Although entirely procedural grounds of judicial review may still be validly raised as objections; Council of Civil Service Unions v Minister for the Civil Service (1985) 1 AC 374 at 411-412.
  4. Review Publishingsupra note 2.
  5. Ibid at (98).
  6. (2016) 1 SLR 779.
  7. Ibid at (94).
  8. Ibid at (97) (emphasis added).
  9. Ibid at (1).
  10. Article 35(8) of the Constitution of the Republic of Singapore (1965 Rev Ed).
  11. (2008) 2 SLR(R) 239 at (148).
  12. Admittedly, it has always been maintained that exercises of the prosecutorial power in a manner which constitutes unequal treatment under Art 12 would also be reviewable (ibid at (148); Ridzuan bin Mohd Ali v Attorney-General (2015) 5 SLR 1222 at (35)), and it is clear that Article 12’s reasonable classification test does comport a preliminary inquiry into the rationality of executive actions insofar as its intelligible differentia limb precludes differentia “so unreasonable as to be illogical and/or incoherent” (see Lim Meng Suang v Attorney-General (2015) 1 SLR 26 at (67)). However, such rationality review under Art 12 would only impugn executive acts which in fact differentiate between individuals or classes of people, and would only arise from an express constitutional mandate rather that something inherent in Singapore’s concept of the rule of law – unlike rationality review under administrative law principles, which are applicable simply by virtue of the nature of Singapore’s rule of law.
  13. Phyllis Tansupra note 11 at (148).
  14. Ibid at (138) and (150(c)).
  15. Ibid at (150(d)) (emphasis added).
  16. (2012) 2 SLR 49 at (17).
  17. Ibid at (47).
  18. Ibid at (44)-(46) (emphasis added).
  19. (Cap 185, 2008 Rev Ed).
  20. Ibid s 33B, generally.
  21. Singapore Parliamentary Debates, Official Report (14 November 2012), “Second Reading, Public Order Bill” vol 89 at 1:49 pm (K Shanmugam, Minister for Law).Jaclyn L Neo, “Autonomy, Deference and Control: Judicial Doctrine of Separation of Powers in Singapore” (2018) 5 Journal of International & Comparative Law 461 at 464.
  22. Ridzuansupra note 12 at (76).
  23. (2017) 1 SLR 173 at (98)-(99).
  24. (2018) SGHC 112.
  25. Ibid at (31).
  26. Jaclyn L Neo, “Autonomy, Deference and Control: Judicial Doctrine of Separation of Powers in Singapore” (2018) 5 Journal of International & Comparative Law 461 at 464.
  27. Chng Suan Tze v Minister for Home Affairs (1988) 2 SLR(R) 525 at (86). See also Tan Seet Eng (2016) 1 SLR 779 at (1)-(2).
  28. (2016) 3 SLR 598 at (58) (emphasis added).
  29. Instead of accepting an additional ground of judicial review concerning substantive legitimate expectations; ibid at (58)-(59).
  30. Nagaenthran HCsupra note 25 at (88) and (99).
  31. Ibid at (96).
  32. Ibid at (94).
  33. Neo, supra note 26 at 467.
  34. See Lee Zhe Xu, “When is an Ouster Clause Ousted?” (6 July 2018) (http://www.singaporelawblog.sg/blog/article/214) and Benjamin Joshua Ong, “The constitutionality of ouster clauses: Nagaenthran a/l K Dharmalingam v Attorney-General (2018) SGHC 112” (2019) Oxford University Commonwealth Law Journal (forthcoming) for doctrinal treatments of the issue.
  35. Supra note 5.
  36. Civil Appeal No. 98 of 2018, heard 24 January 2019.
  37. These statements were distilled from the author’s written notes from his attendance at the Court of Appeal’s hearing for Nagaenthran, which were cross-checked with those of his colleagues Ariffin Sha and Joshua Chow, and which are on file with the author.
  38. Respondent’s Case in Civil Appeal No. 98 of 2018, filed 9th November 2018, at (24)-(29) and (50)-(57). The Attorney-General’s secondary argument as that, even if the relevant field of expertise was justiciable, rationality review should be precluded if a statutory provision so required; at (30)-(33) and (58)-(59).
  39. Author’s attendance notes at Nagaenthran CAsupra note 37.
  40. Ibid.