Entrenched clause

An entrenched clause or entrenchment clause of a basic law or constitution is a provision which makes certain amendments either more difficult or impossible, i.e., inadmissible. It may require a form of supermajority, a referendum submitted to the people, or the consent of another party.

An entrenched clause whose intent is to prevent subsequent amendments, will, once it is adopted, and provided that it is correctly drafted, make some portion of a basic law or constitution irrevocable except through the assertion of the right of revolution.

Any amendment to a basic law or constitution which would not satisfy the prerequisites enshrined in a valid entrenched clause would lead to so-called "unconstitutional constitutional law", i.e. an amendment to constitutional law text which would appear to be constitutional law only by its form, albeit being unconstitutional as with respect to the procedure in which it has been enacted, or as to the material content of its provisions.

Entrenched clauses are, in some cases, justified as protecting the rights of a minority from the dangers of majoritarianism or in other cases, the objective may be to prevent amendments to the basic law or constitution which would pervert the fundamental principles enshrined in it, in particular to prevent the creation of a legalistic dictatorship. But entrenched clauses are often challenged by their opponents as being undemocratic.

Eternity clauses are a type of entrenched clause.

As Australian Parliaments have inherited the British principle of parliamentary sovereignty, they may not entrench themselves by a regular act. Therefore, the entrenchment of the national flag in the Flags Act 1953 is without force as the entrenchment clause could be removed (through normal legislative amendment) by later parliaments.

The Commonwealth (i.e. federal) Constitution is entrenched as it may only be amended by referendum; the amendment must gain the support of a majority of Australian voters nationwide, plus a majority of voters in a majority of states. These provisions are specified in section 128. The Imperial Parliament's power to amend it in Australian law has been revoked by the Statute of Westminster Adoption Act 1942 and the Australia Act 1986.

...
Wikipedia