In the decision Vanderstock v Victoria [2023] HCA 30, the High Court held by a narrow 4:3 majority that a tax imposed by Victoria on the use of electrical and hybrid vehicles (EVs) was invalid. The decision is significant because the majority reopened and overruled previous High Court authority to reach that conclusion. It is also significant because it may affect the validity of other state taxes. This article, a precursor to a seminar of the same name, published in Proctor briefly explains the decision and its implications.