It has been an eternal quest to limit the powers of the executive. In the ‘new Westminsters’² of the Commonwealth, the Montesquieuan model of separation of powers was theoretically influential and yet practically avoided, as in the UK. Aside from the US and Westminster models, Bruce Ackerman has argued of a third model of democratic governance in the wake of the Second World War: constrained parliamentarism. This model sits between the presidentialist American form of Montesquieu and the parliamentary sovereignty that affords the British executive a near elective dictatorship. Constrained parliamentarism ‘rejects the US separation between executive and legislature and