Chapter 4 of the Protocol imposes on States Parties two distinct sets of obligations. The first mandates legislative measures of a specifically penal nature, the second legislative and other measures which may include those of a penal nature.

The first range of obligations are those attaching to the five ‘serious violations’ of the Protocol defined in article 15 (1). These obligations are to be found articles 15 (2) to 19.

The second set of obligations are those attaching to the two ‘other violations’ referred to in article 21. These obligations are to be found in article 21 itself.