Issues in relation to which referendums are mandatory at the national level

Saint Kitts and Nevis
- Constitutional amendments
- Secession
Federation of Saint Kitts and Nevis Constitutionalorder of 1983
(Adopted in June 22, 1983)
http://pdba.georgetown.edu/constitutions/kitts/kitts83.html
Article38(3).
Abill to alter this section, schedule 1 to this Constitution or any of theprovisions of this Constitution specified in Part 1 of that schedule or any ofthe provisions of the Supreme Court Order specified in Part 2 of that scheduleshall not be submitted to the Governor-General for his assent unless-
a)there has been an interval of not less than ninety days between theintroduction of the bill in the National Assembly and the beginning of theproceedings in the Assembly on the second reading of the bill; and
b)After it has been passed by the Assembly the bill has been approved on areferendum by not less than two-thirds of all the votes validity cast on thatreferendum in the island of Saint Christopher and two-thirds of all the votesvalidly cast on that referendum in the island of Nevis.
Article 113(1) and (2).
TheNevis Island Legislature may provide that the island of Nevis shall cease to befederated with the island of Saint Christopher and accordingly that thisConstitution shall no longer have effect in the island of Nevis.
(2)A bill for the purposes of subsection (1) shall not be regarded as being passedby the Assembly unless on its final reading the bill is supported by the votesof not less than two-thirds of all the elected member of the Assembly and sucha bill shall not be submitted to the Governor-General for his assent unless[…]
b)after it has been passed by the Assembly, the bill has been approved in areferendum held in the island of Nevis by not less than two-thirds of all thevotes validly cast on that referendum;
Areferendum is mandatory if Nevis wishes to cease to be part of the federation.