This paper argues that the Canadian judiciary engages in a form of constitutional abnegation by insisting that international investment law, as represented by NAFTA’s investment chapter, plays no role in Canada’s constitutional order. By conferring rights upon investors, enforceable against states in private arenas, for breach of investment treaty obligations, states are subject to the disciplines that sometimes mimic, and other times go well beyond, those found in dominant national constitutional systems. The Canadian judiciary lacks the courage – ‘constitutional courage,’ in Harry Arthur’s words – to admit that external legal regimes can have the effect of significantly transforming domestic constitutionalism. To illustrate, I take up constitutional litigation initiated by the Council of Canadians, the Canadian Union of Canadian Union of Postal Workers, and the Charter Committee on Poverty Issues challenging the consistency NAFTA’s investment chapter with Canada’s constitution. Predictably, their arguments were dismissed by various levels of court on the basis that international law and domestic constitutional law operate in ‘different spheres.’ It turns out that, according to these judges, the international investment regime has no connection with constitutionalism here or abroad.