INDIRECT ENCROACHMENT ON FEDERAL AUTHORITY 235 This common has aheady been pointed out in discussing taxes on privileges,^ and there will be occasion to refer to it again. It is also to be borne in mind that no exercise of state fiscal power can adequately be judged in isolation. The legitimacy of any particular demand may depend upon the presence or absence of some other or others. But threads must first be spun before they can be woven together. If any misapprehensions are permitted or fostered by the effort to disentangle in analysis what is inter- related in practice, they will, it is hoped, be dispelled by a later venture in synthesis. The taxes on property here to be considered do not include those levied on the property that is carried in interstate commerce and offered for sale after reaching its destination. Such taxes, with the exception of those which in some fashion discriminate against interstate commerce,^ are not treated as instances of inditect encroachment on the realm of federal control. Property in inter- state transit^ and property that has completed its journey^ present the issue of taxability rather than that of valuation. What we are here concerned with are the taxes which are confessedly on proper subjects of state power, but which are assessed in ways that are alleged to exceed that power. The issue is whether the subject or the method of assessment shall be regarded as controlling. The property taxes which raise this issue are those on property which is an instrument of interstate commerce, whether peri- patetic like cars and engines or immobile hke ties and track. When property of an intangible character intrudes itself into the dis- cussion, it is because the Supreme Court has chosen to make a classification for which it must bear the responsibility. On December 15, 1873, ^^ Union Pacific R. R. Co. v. Peniston, a majority of the Supreme Court rejected the contention that the property of the Union Pacific was exempt from state taxation on account of the relation of the road to the federal government. '31 Hahv. L. Rev. 768, note 166.
- See 31 Harv. L. Rev. 572-74.
- See editorial note in 26 Harv. L. Rev. 358-60.
« Brown v. Houston, 114 U. S. 622, 5 Svp. Ct, Hep. 109 (1885). ^ 18 Wall. (U. S.) 5 (1873). -See 31 Harv. L. Rev. 371, note 171.
