Recent changes to Canada's general anti-avoidance rule (GAAR) on their face broaden the scope of GAAR, making it applicable to more tax-minimization schemes. However, developments in Australia, home of the modern GAAR, and case law in Canada suggest that the impact of the changes may be limited. In particular, the extension of GAAR to arrangements where tax minimization is not necessarily the primary objective of the transaction but merely one of the main purposes may prove to be unworkable. The purpose of a transaction is ultimately a subjective factor, whatever objective indicators are considered, and the only person able to assert the true purpose of an arrangement is the taxpayer. Equally obvious is the reality that tax minimization is the goal of only some steps in a commercial arrangement, and if the taxpayer can replace the investigation of the impugned transactions with the broader commercial arrangement—sell an asset, borrow money, and so forth—the main purpose will almost always be a legitimate commercial goal. More significantly, an examination of Australian and Canadian case law reveals that the courts consistently make a distinction between arrangements that are implicitly endorsed by the legislature and those that clearly fall outside possibilities contemplated by Parliament, allowing GAAR to apply only in the latter cases. For example, if the legislature and tax authorities allow taxpayers to treat finance leases as operating leases, the courts will not permit tax authorities to use GAAR to stop an egregious exploitation of the legal myth. If the legislature provides imputation credits for dividends and taxpayers structure financing to enjoy the benefit, the courts will not step in to restrict access where the legislature has not imposed statutory limits. Conversely, if the legislature has set out clear and unambiguous rules on when losses can be transferred, courts will allow tax authorities to use GAAR to strike down arrangements seeking to bypass those rules. Experience shows the courts are quite willing to allow the use of GAAR as a shield where taxpayers devise schemes that abuse concessions in the law through contrived arrangements that seek to extend the concessions to arrangements far from those for which the concessions were intended. The courts will not, however, allow the government to use GAAR as a sword to extend tax liability to arrangements that are clearly excluded through gaps or errors in the law. The message from the courts is unambiguous: if a mistake was made in the law or a treaty, it should be fixed by way of amendment, not GAAR. In short, the apparent overhaul of the Canadian GAAR may prove to be little more than a tempest in a teacup with little and perhaps no impact on dispute outcomes.