Claim: Brunei is a country.

A federated state -LRB- which may be referred to as a state , a province , a canton , a Land , etc. -RRB- is a territorial and constitutional community forming part of a federation . Such states differ from fully sovereign states , in that they have transferred a portion of their sovereign powers to a federal government . Importantly , when states choose to federate , they lose their standing as persons of international law . Instead , the federal union as a single entity becomes the sovereign state for purposes of international law . A federated state holds administrative jurisdiction over a defined geographic territory and is a form of regional government .   In some cases , a federation is created from a union of political entities , which are either independent , or dependent territories of another sovereign entity -LRB- most commonly a colonial power -RRB- . In other cases , federated states have been created out of the regions of previously unitary states . Once a federal constitution is formed , the rules governing the relationship between federal and regional powers become part of the country 's constitutional law and not international law .   In countries with federal constitutions , there is a division of power between the central government and the component states . These entities - states , provinces , cantons , Länder , etc. - are partially self-governing and are afforded a degree of constitutionally guaranteed autonomy that varies substantially from one federation to another . Depending on the form the decentralization of powers takes , a federated state 's legislative powers may or may not be overruled or vetoed by the federal government . Laws governing the relationship between federal and regional powers can be amended through the federal constitution and state constitutions .