A mild intellectual disability does not necessarily reduce moral culpability or moderate deterrence where the offender's intoxication, rather than the disability, was the operative cause of the offending. The existence of an intellectual disability does not logically compel the conclusion that the impairment contributed in a material sense to the offending. Significant differences in co-offenders' personal circumstances — particularly an acquired brain injury suffered in custody attracting all Verdins limbs — can justify a marked sentencing disparity without breaching the parity principle.
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