Canada’s Parliament plays little but a perfunctory role in the adoption of tax treaties, even though these agreements have significant impact on Parliamentary autonomy over core national budgetary matters as well as core legal and administrative functions. This article argues that Canada’s tax treaty process reflects a studied and intentional preference against public engagement in international fiscal policy, and that this stance has a negative impact on the rule of law. The article demonstrates the governance issue posed by lack of meaningful Parliamentary oversight using a recent departure from stated treaty policy, namely, the passage of a controversial agreement to implement the Foreign Account Tax Compliance Act (FATCA), an aggressive and extra-territorial regulatory regime imposed on Canadian financial institutions by the United States. The article examines the implications of Canada’s approach to this and other tax-related agreements and concludes that a much more engaged and informed Parliament is vitally necessary to achieve integrity in Canada’s treaty process.