Some federal constitutions also provide that certain constitutional amendments cannot occur without the unanimous consent of all states or of a particular state. The US constitution provides that no state may be deprived of equal representation in the senate without its consent. In Australia, if a proposed amendment will specifically impact one or more states, then it must be endorsed in the referendum held in each of those states. Any amendment to the Canadian constitution that would modify the role of the monarchy would require unanimous consent of the provinces. The German Basic Law provides that no amendment is admissible at all that would abolish the federal system.

The US Constitution says what to amendments?