For example, a proposal to create a supreme bill of rights that would grant courts the ability to invalidate Acts of Parliament via judicial review was rejected. Parliament still functions as the supreme lawmaker. The last major constitutional reform of the Fourth Labour Government was the New Zealand Bill of Rights Act 1990 (NZBORA). The NZBORA puts New Zealand's commitment to the 1977 International Covenant on Civil and Political Rights (ICCPR) into effect in New Zealand law. However, the Act is neither entrenched nor supreme law (as was mooted in the White Paper of 1985) and can, therefore, be repealed by a simple majority of Parliament. Reform Because it is not supreme law, New Zealand's constitution is in theory comparatively easy to reform, requiring only a majority of Members of Parliament to amend it, as illustrated by the abolition of the Legislative Council in 1950. Certain aspects of the constitution are entrenched, after a fashion. Section 268 of the Electoral Act declares that the law governing the maximum term of Parliament (itself part of the Constitution Act), along with certain provisions of the Electoral Act relating to the redistribution of electoral boundaries, the voting age, and the secret ballot, may only be altered either by three-quarters of the entire membership of the House of Representatives, or by a majority of valid votes in a popular referendum. Section 268 itself is not protected by this provision, so a government could legally repeal Section 268 and go on to alter the entrenched portions of law, both with a mere simple majority in Parliament. However, the entrenchment provision has enjoyed longstanding bipartisan support, and the electoral consequences of using a legal loophole to alter an entrenched provision would likely be severe. Even though it is not legislatively entrenched, a material change to other aspects of the constitution is unlikely to occur absent broad-based support, either through broad legislative agreement or by referendum. Referendums There is no requirement for a referendum to enact constitutional change in New Zealand, except for the electoral system and term of parliament. However, there have been several referendums in New Zealand's history, most recently to decide the nature of electoral reform in New Zealand. Many groups advocate constitutional reform by referendum, for example New Zealand Republic supports a referendum on a republic. The Privy Council as New Zealand's highest court of appeal was replaced by the Supreme Court of