Article 12 of the Constitution of Singapore

Article 12 of the Constitution of the Republic of Singapore guarantees to all persons equality before the law and equal protection of the law. The Article also identifies four forbidden classifications – religion, race, descent and place of birth – upon which Singapore citizens may not be discriminated for specific reasons. For example, discrimination on those classifications is prohibited in the appointment to any office or employment under a public authority or in the administration of any law relating to the establishing or carrying on of any trade, business, profession, vocation or employment.

Persons unable to show that one of the forbidden classifications applies to them may try to argue that they are members of a group defined by a law in a way that violates the general guarantee of equality and equal protection. To succeed, they must establish that the classification used in the law fails the rational nexus test, which is a three-stage test formulated by the courts. The first stage of the test involves an examination as to whether the law differentiates amongst classes of individuals. At the second stage, the court considers if the differentiation is founded on an intelligible or distinguishing feature. Finally, the basis of the differentiation must bear a reasonable relation to the object of the statute. However, the test is not foolproof as a classification may satisfy the test even if the object of the law is itself illegitimate. The rational nexus test, as it is currently applied in Singapore, also tolerates over- and under-inclusive classifications. It remains to be seen if local courts will consider other approaches to the issue, such as the three-tier system of scrutiny applied in the United States, the proportionality analysis applied in the United Kingdom to other areas of human rights law, or the reasonableness approach taken by some judges in India and Malaysia.

The rational nexus test does not apply where a statute treats all persons equally, but it is alleged that the authorities have applied the statute in a discriminatory manner. Instead, a modified rational nexus test is used, which requires a court to consider whether there is a reasonable nexus between the state action taken and the object of the law. Such a nexus will be absent if the action amounts to intentional and arbitrary discrimination or intentional systematic discrimination. It is insufficient if any inequality is due to inadvertence or inefficiency, unless this occurs on a very substantial scale. In addition, inequalities arising from a reasonable administrative policy or which are mere errors of judgment are insufficient to constitute a violation of Article 12(1).

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