United Democratic Movement v President of the Republic of South Africa and Others

Following political realignments after the 1999 national and provincial elections and the 2000 municipal elections, Parliament enacted four pieces of legislation in June 2002 to permit limited 'floor crossing' by members of national, provincial and local government without loss of their seats. These included two constitutional amendments and two ordinary Acts. The legislation allowed party representatives to change party allegiance during specified 15-day windows, subject in some cases to a 10% threshold. The United Democratic Movement (UDM) challenged the constitutionality of this legislation, arguing that it undermined proportional representation, multi-party democracy, the rule of law, and voters’ rights. The Cape High Court suspended the operation of the Acts, and the matter was brought urgently before the Constitutional Court.

The application by the United Democratic Movement was dismissed. The constitutional amendments and related legislation permitting limited floor crossing were declared constitutionally valid.

This case is a leading authority on the constitutional status of floor crossing in South Africa. It affirms Parliament’s wide power to amend the Constitution under section 74, rejects a rigid basic structure doctrine, and clarifies that proportional representation and anti-defection rules are policy choices rather than entrenched constitutional requirements. The judgment underscores judicial deference to constitutional amendments properly enacted.