The ability of a federal government to create national institutions that can mediate differences that arise because of linguistic, ethnic, religious, or other regional differences is an important challenge. The inability to meet this challenge may lead to the secession of parts of a federation or to civil war, as occurred in the United States (southern states interpreted slavery under the tenth amendment as a state right, while northern states were against slavery, with a catalysis occurring in the then–Kansas Territory), in Nigeria and in Switzerland. In the case of Malaysia, Singapore was expelled from the federation because of rising racial tension. In some cases, internal conflict may lead a federation to collapse entirely, as occurred the Federation of Rhodesia and Nyasaland, the Gran Colombia, the United Provinces of Central America, and the West Indies Federation.