Abstract
The ‘proper’ role for an elected representative is a long debated question, one which has been made even more complicated by the domination of the electoral process by mass membership political parties. In the wake of New Zealand's adoption of the mixed member proportional voting system, that country has chosen to prescribe through legislation a ‘party team mandate’ role for Members of Parliament (MPs). This ‘party hopping law’ requires any MP who leaves the party for which he or she was elected also to leave his or her seat in Parliament. However, the use of legal regulation to impose a fixed representative ideal upon MPs has led to a number of negative consequences for New Zealand's political processes. This article examines the theory behind the party hopping law, outlines the reasons why it was enacted, traces the concrete consequences of its adoption, and draws some broader lessons as to the limits of legal regulation in the electoral arena.