The Reference re Supreme Court Act and the Reference re Senate Reform have often been interpreted as widening the body of norms that form part of the Constitution. The author submits that in those two references, the Supreme Court of Canada has instead given effect to the protective function of the constitutional amending formula. This means that the amending formula limits the action of Parliament and the provincial legislatures. A historical and purposive interpretation of sections 41 and 42 of the Constitution Act, 1982, leads to the conclusion that the framers of the Constitution intended to limit the power of Parliament and the provincial legislatures to affect certain essential characteristics of the main components of Canada’s political system. The author then spells out the consequences of this reading of the two references on possible reforms of the Supreme Court, the federal judiciary, the Senate and the electoral system.