Kenya Criminal Law: Legality and the Constitution

The Kenyan Constitution is committed to the principle of legality, with, for example, its provision that "every accused person has a right to a fair trial, which includes the right
1."not to be convicted for an act or omission that was not an offence under either national or international law at the time it was committed or omitted; [and]."
2.to the benefit of the least severe of the prescribed punishments if the prescribed punishment for the offence has been changed between the time that the offence was committed and the time of sentencing."In terms of theius certumprinciple, the crime must not, as formulated, be vague or unclear,so that the subject may understand exactly what is expected of him.

Although the Constitution does not expressly provide that vague or unclear penal provisions may be struck down, it is "quite possible and even probable," that the first provision above will be interpreted in such a way that vaguely defined statutory crimes may be declared nulland void. This "void-for-vagueness" rule may be based either on the right to a fair trial in general or on the principle that, if a criminal norm in legislation is vague and uncertain, it cannot be stated that the act or omission in question actually constituted an offence priorto a court's interpretation of the legislation.To comply with the requirement of sufficient clarity, one should bear in mind
1.that absolute clarity is not required, and reasonable clarity is sufficient; and
2.that a court, in deciding whether a provision is clear or vague, should approach the legislation on the basis that itis dealing with reasonable people, not foolish or capricious ones.It is not only statutory criminal provisions that may, on the ground of vagueness, be declared null and void in terms of the Constitution, but also provisions of common law that are vague and uncertain.