When does a person have an intellectual disability? The insights of the US Supreme Court

by | Apr 15, 2019

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About Martin Kwan

Martin Kwan is a legal researcher currently focusing on public, human rights and electoral laws.


Martin Kwan, “When does a person have an intellectual disability? The insights of the US Supreme Court” (OxHRH Blog, 15 April 2019), <https://ohrh.law.ox.ac.uk/when-does-a-person-have-an-intellectual-disability-the-insights-of-the-us-supreme-court> [date of access].

A death sentence against a convict with an intellectual disability (ID) would violate the Eighth Amendment’s proscription of cruel and unusual punishments, because it would serve no penological purpose. In the recent US Supreme Court (SC) decision of Moore v Texas, the issue was (once again, having been litigated before in 2017) the correctness of the Texas Court of Criminal Appeals (CCA)’s approach to determining whether the defendant, who had been convicted of the murder of a store employee during a robbery, had an intellectual disability.

The legal test (derived from medical guidelines) for ID has three criteria, basically requiring (1) deficits in intellectual functioning (e.g. an IQ test), (2) adaptive deficits, and (3) the onset of these while still a minor. Moore has a marginally low IQ of 74, so the first and third criteria are met. The debate concerned the second criterion. In terms of the deficit, at 13, Moore lacked understanding of time and seasons, subtraction as the reverse of addition, standards of measure, could not keep up with lessons, with limited ability to read and write, slow speech, and had dropped out during ninth grade. Yet, Moore had a girlfriend, had a job, played pool for money, mowed lawns for money, lived on the streets, provided his accomplices with firearms, killed and robbed, wore a wig, concealed the weapon, and fled after the crime. How should the court deal with these adaptive strengths?

It was held that the CCA’s approach for the second criteria was (again as in 2017) wrong in two aspects, namely (1) the approach had to be medically-informed, rather than based on lay perceptions of ID, and (2) specifically, it was wrong to over-emphasise on the adaptive strengths, because the medical approach would consider the deficits only. Whilst the SC said the strengths cannot be ‘over-emphasized’, the tenor of the judgement strongly suggests that it cannot be emphasised at all (see the observations of the dissent). As such, it was held that Moore has an ID.

The ‘medical model’ of disability would see impairment itself as a disability. The SC’s approach is essentially an application of the medical model, because they both focus on the medical aspect, and in particular the deficit. The test of looking at what one cannot do (deficit) forms a striking contrast with the way disability is defined under the ‘social model’ of disability (e.g. adopted by the UN Convention on the Rights of Persons with Disabilities, and the Americans with Disabilities Act). The ‘social model’ sees impairment as different from disability. One is disabled not by his/her own impairment, but by the social barriers which fails to fully integrate individuals into society. In the context of ID, the relevant barriers may include questionable notions of intelligence and social competence. Thus, the social model would encourage equalisation and inclusion by shifting the focus to removing barriers.

The SC’s approach essentially turns back to the thrust of the problem that the social model aims to eradicate: one is disabled solely by virtue of  his/her deficit/impairment. The test is a negative evaluation, because it does not (also) emphasise what one can do. It puts the ‘fault’ of disability on one’s mind and ability, as personal traits, focusing on what one cannot do. The social implication is that even if a person (and society) works hard to remove intelligence barriers and is able to adapt to a “normal” life (especially when the social model promotes independent living), he/she is still legally disabled intellectually. Thus, this does not promote impaired people’s self-worth and makes it harder for such individuals to feel good about themselves.

Whilst the SC justifies a more inclusive approach for preventing persons with ID to be executed, it has, however, ignored the human rights and social perspective of the test. A more inclusive approach that includes more people as disabled may not be desirable, as many medically-impaired people do not want to see themselves as disabled.

It is suggested that it would be better to take a holistic approach taking into account also the strengths of people with disabilities. After all, in Shakespeare and Watson’s words, disability ‘is a complex dialectic of biological, psychological, cultural and socio-political factors, which cannot be extricated except with imprecision’. It ‘should not be reduced to a medical condition’ or ‘an outcome of social barriers alone’.

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