13 African Charter on the Rights and Welfare of the Child.12 The principles fundamental to these instruments have found articulation in our Constitution. [17] The rules and guidelines set out in these international instruments are detailed and provide specific suggestions for the realisation of the broad goals that it embodies. Since its introduction the CRC has become the international benchmark against which legislation and policies can be measured. Traditional theories of juvenile justice now have a new 'framework within which to situate juvenile justice: a children's rights model'.13 [18] The principle that detention is a matter of last resort (and for the shortest appropriate period of time) is the leitmotif of juvenile justice reform.14 Those principles are articulated in international law15 and are enshrined in s28(1)(g) of the Constitution which reads: '[E]very child has the right not to be detained except as a measure of last resort, in which case ..... the child may be detained only for the shortest appropriate period of time, ....'. [19] Guiding principles must therefore include the need proportionality (see S v Kwalase 2000 (2) SACR 135 (C)). 12 The Charter was ratified by the South African Parliament on 18 November 1999. Sloth-Nielsen op cit Law, Democracy and Development at 66. 14 Sloth-Nielsen op cit Law, Democracy and Development 78. 15 Article 37(b) of the CFC; Beijing Rule 17.1 13 for The