INDIRECT ENCROACHMENT ON FEDERAL AUTHORITY 643 guilty of the inequalities of burden that would ensue from allowing to no one any deduction from gross receipts. This brings us to the element in the Wisconsin income tax that the Supreme Court did not mention. Nothing was said in the opinion in the Oak Creek case about the extent to which the tax was in lieu of other demands. There is no hint that a state has to exempt property of any kind in order to include receipts from in- terstate commerce in a general tax on net incomes. Yet the Su- preme Court was undoubtedly aware of the fact that the Wisconsin tax was one substantially in lieu of all other taxes on chattels and intangibles. In Northwestern Mutual Life Insurance Co. v. Wis- consin ^^ the opinion of Mr. Justice Day quoted a statement from the Wisconsin supreme court to the effect that the Income Tax Law "marked the abandonment of the attempt to levy personal prop- erty taxes upon" securities and credits.^^ Whether it was called to the attention of the Supreme Court that Wisconsin also allowed taxes on chattels to be deducted from the assessment of the in- come tax does not appear; but such was the case,^° and the Supreme Court would hardly have neglected to inquire about it had it been regarded as important. The general nature of the Wisconsin tax was thus summarized by Chief Justice Winslow of the Wisconsin supreme court in an opinion rendered in 191 2: " By the present law it is quite clear that personal property taxation is for all practical purposes becoming a thing of the past. The specific exemptions of all money and credits and the great bulk of stocks and bonds, as well as of all farm machinery, tools, wearing apparel, and household furniture in actual use, regardless of value, goes far to elimi- nate taxation of personal property; while the provision that he who pays personal property taxes may have the amount so paid credited on his income tax for the year seems to put an end to any effective taxation of personal property. That taxation of such property has proven a practical failure will be admitted by all who have given any attention to the subject. Doubtless this was one of the main arguments in the legislative mind for the passage of the present act. By this act the legislature has, in substance, declared that the state's system of taxa- tion shall be changed from a system of uniform taxation of property (which so far as personal property is concerned has proven a failure) to ^* 247 U. S. 132, 38 Sup. Ct. Rep. 444 (1918). 2' 247 U. S. 132, 136, 38 Sup. Ct. Rep. 444 (1918). '° Wisconsin Stat. (1915), chap. 48 a, § 1087 m-26.
