CERTIORARI TO THE SUPREME COURT OF TENNESSEE.
Hughes, McReynolds, Stone, Roberts, Black, Reed, Frankfurter, Douglas, Murphy
MR. JUSTICE FRANKFURTER delivered the opinion of the Court.
This case is here to review a judgment of the Supreme Court of Tennessee sustaining an assessment of petitioner's property, tangible and intangible, under that state's ad valorem tax law. All Tennessee property is subject to such a tax; but there are two schemes of procedure for making assessments, one for public service corporations and one for other taxpayers. As to ordinary property the task of valuation rests upon officials of the various counties. For public service corporations the assessments
must be made by the Railroad and Public Utilities Commission, which is commanded to ascertain the "actual cash value" of corporate property situated in Tennessee. Tennessee Code, § 1526. Since petitioner operates an interstate railroad, the value of its entire system and not merely of that portion within Tennessee had first to be ascertained. This the Commission estimated at $23,996,604.14. From this figure was deducted the value of petitioner's "localized" property, that is, its terminal buildings, shops, and non-operating real estate. The remaining sum served as the base for calculating the value of what in the language of Tennessee law is called the utility's "distributable" property attributable to Tennessee, § 1528, which the Commission ascertained by taking the ratio which petitioner's mileage in Tennessee bears to its total mileage. This was found to be $12,925,944; and that is the amount of the assessment here in dispute. From this action by the Commission petitioner appealed, in accordance with the local statute, to the State Board of Equalization, respondent here. After hearing and by formal opinion, the Board confirmed the Commission's valuation.
In anticipation of a certification by the Board of its final assessment preliminary to the collection of taxes based upon it, the Railway brought an appropriate proceeding in the state courts to set aside what it claimed was the void "excess of the fair taxable value" of its property. This suit was dismissed by the trial court and its judgment was affirmed by the Supreme Court of Tennessee with two justices separately dissenting. 140 S. W. 2d 781. Because of petitioner's claim that the result below was inconsistent with decisions of this Court, we granted certiorari. 309 U.S. 651. The assessment was contested below on objections grounded in both state and federal constitutions. Here, of course, only federal questions are open. Petitioner claims that the challenged
assessment violates the Fourteenth Amendment in its guarantees of due process and the equal protection of the laws, and is offensive to the Commerce Clause.
We shall first consider the claim based on the historic implications of the Commerce Clause as a limitation upon the state's taxing power. Petitioner argued that Tennessee has taxed values which are in truth outside its borders, thereby burdening that which the Commerce Clause has left free. The guiding principles for adjustment of the state's right to secure its revenues and the nation's duty to protect interstate transportation are by this time well settled. The problem to be solved is what portion of an interstate organism may appropriately be attributed to each of the various states in which it functions. Basic to the accommodation of these conflicting state and national interests is realization that by its very nature the problem is incapable of precise and arithmetical solution. In tapping these common sources of revenue a state cannot, we have held, use a fiscal formula, whatever may be its appearance of certitude, to project the taxing power of the state plainly beyond its borders. Wallace v. Hines, 253 U.S. 66. In the light of these principles, Tennessee has not overstepped its bounds.
In basing its apportionment on mileage, the Tennessee Commission adopted a familiar and frequently sanctioned formula. Pullman's Car Co. v. Pennsylvania, 141 U.S. 18; Maine v. Grand Trunk Ry. Co., 142 U.S. 217; Pittsburgh, C., C. & St. L. Ry. Co. v. Backus, 154 U.S. 421; Branson v. Bush, 251 U.S. 182. See 2 Cooley on Taxation, pp. 1660-64. Its asserted inapplicability to the particular situation is rested on petitioner's evidence as to the comparative revenue-producing capacity of its lines in and out of Tennessee. But both the Commission and the Supreme Court of the state thought that this evidence, however weighty, was insufficient to displace the relevance of the formula. In a matter where exactness is concededly
unobtainable and the feel of judgment so important a factor, we must be on guard lest unwittingly we displace the tax officials' judgment with our own. Certainly we cannot say that the combined judgment of Commission, Board, and state courts is baseless. Wherever the states' taxing authorities have been held to have intruded upon the protected domain of interstate commerce in their use of a mileage formula, the special circumstances of the particular situation, in the view which this Court took of them, precluded a defensible utilization of the mileage basis. ...