議院内閣制
The political structure for the Federation of Saint Kitts and Nevis is based on the Westminster Parliamentary system, but it is a unique structure in that Nevis has its own unicameral legislature, consisting of Her Majesty's representative (the Deputy Governor General) and members of the Nevis Island Assembly. Nevis has considerable autonomy in its legislative branch. The constitution actually empowers the Nevis Island Legislature to make laws that cannot be abrogated by the National Assembly. In addition, Nevis has a constitutionally protected right to secede from the federation, should a two-thirds majority of the island's population vote for independence in a local referendum. Section 113.(1) of the constitution states: "The Nevis Island Legislature may provide that the island of Nevis shall cease to be federated with the island of Saint Christopher and accordingly that this Constitution shall no longer have effect in the island of Nevis."