CHAP. 11] THE COMMONWEALTH OF AUSTRALIA 825
to consider the validity under the Constitution of the pro-
visions of each Act presented for the royal assent.
The Court also noticed a misapprehension of the Supreme
Court in thinking that, accepting the doctrine of McCulloch
v. Maryland as sound law, it was a question in each case
whether the attempted exercise of state authority actually
impeded the operations of the Federal Government. They
laid down that the question was solely not whether actual
interference took place, but whether interference might take
place!
On these grounds they held that the Stamp Act did actually
interfere with the action of a federal officer in the discharge
of his duty to the Commonwealth. The Federal Audit Act
required the giving of a receipt by the officer, and the Stamp
Act penalized the performer of that duty unless a contribu-
tion were made to the state revenue. The attaching by
a state law of any condition to the discharge of a federal duty
wag assuredly an act of interference or control. If, therefore,
the Tasmanian Act were construed as applying to receipts
given by a federal officer to the Federal Treasurer in the
course of his federal duty, it would be an interference with
him in the exercise of that duty and would, therefore, be
invalid. It was, however, a sound principle that acts of
a sovereign legislature, and indeed of subordinate legislatures,
should be so interpreted as to make them operative and not
inoperative, and the state law must therefore be inter-
preted so as not to apply to a receipt given bv a federal
officer.
The same principle of non-interference by state laws with
the Commonwealth activities was reasserted in the income-
bax case (Deakin v. Webb and Lyne v. Webb).2 In this case it
was decided that an income-tax of a state, so far as it
attempted to tax the salaries of officers of the Commonwealth,
fell within the principle of D’Emden v. Pedder ;% that when
3 state attempted to give to its legislative or executive
authority an operation which, if valid, would fetter, control,
* Contrast Bank of Toronto v. Lambe, 12 App. Cas. 575.
1 C. L. R. 585. *1C L. R. 91.
