During World War I, Barton joined the majority in "Farey v Burvett" (1915), which saw the court adopt a broad view of the federal government's defence power. In "Duncan v Queensland" (1916), he and Isaacs were the only dissenters from the court's interpretation of section 92 of the constitution. With Griffith authoring the majority opinion, the court held that state governments could circumvent the constitution's free-trade provisions simply by banning the movement of goods across state boundaries. Barton expressed a "heavy sorrow" at the court's decision and Isaacs was highly critical. In 1920, after Barton's death, Isaacs led the court in reversing "Duncan", in what became known as the "Engineers case".