Amalgamated Society of Engineers v Adelaide Steamship Co Ltd (commonly known as the Engineers' Case) was a landmark Australian court case decided in the High Court of Australia on August 31, 1920 concerning the Commonwealth's power under s51(xxxv) of the Constitution.
The case came before the Full Court on a case stated under section 18 of the Judiciary Act. The opinion of the Court was written by Isaacs J. He was joined by Knox CJ, Rich & Starke JJ. Higgins J wrote a separate opinion, but came to a similar conclusion. Gavan Duffy J dissented.
The Engineers' Case arose out of a claim lodged by a union of engineers in the Commonwealth Court of Conciliation and Arbitration for an award relating to 843 employers across Australia. In Western Australia, the employers included three governmental employers. The question was whether a Commonwealth law made under the "conciliation and arbitration" power (section 51(xxxv)) could authorise the making of an award binding those three employers.
From a legal perspective, this case is widely regarded as one of the most important cases ever decided by the High Court of Australia, for it swept away the earlier doctrines of implied intergovernmental immunities and reserved State powers, firmly establishing the modern basis for the legal understanding of federalism in Australia.