Tangible Personalty.—A State may tax tangible property located within its borders (either directly through an ad valorem tax or indirectly through death taxes) irrespective of the residence of the owner.415 By the same token, if tangible personal property makes only occasional incursions into other States, its permanent situs remains in the State of origin, and, subject to certain exceptions, is taxable only by the latter.416 The ancient maxim, mobilia sequuntur personam, which had its origin when personal property consisted in the main of articles appertaining to the person of the owner, yielded in modern times to the "law of the place where the property is kept and used." The tendency has been to treat tangible personal property as "having a situs of its own for the purpose of taxation, and correlatively to . . . exempt [it] at the domicile of its owner."417
Thus, when rolling stock is permanently located and used in a business outside the boundaries of a domiciliary State, the latter has no jurisdiction to tax it.418 Further, vessels that merely touch briefly at numerous ports never acquire a taxable situs at any one of them, and are taxable in the domicile of their owners or not at all.419 Thus, where airplanes are continuously in and out of a state during the course of a tax year, the entire fleet may be taxed by the domicile state.420
416 New York ex rel. New York Cent. R.R. v. Miller, 202 U.S. 584 (1906).
418 Union Transit Co. v. Kentucky, 199 U.S. 194 (1905). Justice Black, in Central R.R. v. Pennsylvania, 370 U.S. 607, 619-21 (1962), had his "doubts about the use of the Due Process Clause to . . . [invalidate State taxes]. The modern use of due process to invalidate State taxes rests on two doctrines: (1) that a State is without 'jurisdiction to tax' property beyond its boundaries, and (2) that multiple taxation of the same property by different States is prohibited. Nothing in the language or the history of the Fourteenth Amendment, however, indicates any intention to establish either of these two doctrines . . . And in the first case [Railroad Co. v. Jackson, 74 U.S. (7 Wall.) 262 (1869)] striking down a State tax for lack of jurisdiction to tax after the passage of that Amendment, neither the Amendment nor its Due Process Clause . . . was ever mentioned." He also maintained that Justice Holmes shared this view in Union Transit Co. v. Kentucky, 199 U.S. at 211.
419 Southern Pacific Co. v. Kentucky, 222 U.S. 63 (1911). Ships operating wholly on the waters within one State, however, are taxable there and not at the domicile of the owners. Old Dominion Steamship Co. v. Virginia, 198 U.S. 299 (1905).
420 Noting that an entire fleet of airplanes of an interstate carrier were "never continuously without the [domiciliary] State during the whole tax year," that such airplanes also had their "home port" in the domiciliary State, and that the company maintained its principal office therein, the Court sustained a personal property tax applied by the domiciliary State to all the airplanes owned by the taxpayer. Northwest Airlines v. Minnesota, 322 U.S. 292, 294-97 (1944). No other State was deemed able to accord the same protection and benefits as the taxing State in which the taxpayer had both its domicile and its business situs. Union Transit Co. v. Kentucky, 199 U.S. 194 (1905), which disallowed the taxing of tangibles located permanently outside the domicile state, was held to be inapplicable. 322 U.S. at 295 (1944). Instead, the case was said to be governed by New York ex rel. New York Cent. R.R. v. Miller, 202 U.S. 584, 596 (1906). As to the problem of multiple taxation of such airplanes, which had in fact been taxed proportionately by other States, the Court declared that the "taxability of any part of this fleet by any other State, than Minnesota, in view of the taxability of the entire fleet by that State, is not now before us." Justice Jackson, in a concurring opinion, would treat Minnesota's right to tax as exclusively of any similar right elsewhere.
Conversely, a nondomiciliary State, although it may not tax property belonging to a foreign corporation which has never come within its borders, may levy a tax on movables which are regularly and habitually used and employed therein. Thus, while the fact that cars are loaded and reloaded at a refinery in a State outside the owner's domicile does not fix the situs of the entire fleet in that State, the State may nevertheless tax the number of cars which on the average are found to be present within its borders.421 But no property of an interstate carrier can be taken into account unless it can be seen in some plain and fairly intelligible way that it adds to the value of the road and the rights exercised in the State.422 Or, a state property tax on railroads, which is measured by gross earnings apportioned to mileage, is constitutional unless it exceeds what would be legitimate as an ordinary tax on the property valued as part of a going concern or is relatively higher than taxes on other kinds of property.423
421 Johnson Oil Co. v. Oklahoma, 290 U.S. 158 (1933). Moreover, in assessing that part of a railroad within its limits, a State need not treat it as an independent line valued as if it was operated separately from the balance of the railroad. The State may ascertain the value of the whole line as a single property and then determine the value of the part within on a mileage basis, unless there be special circumstances which distinguish between conditions in the several States. Pittsburgh C.C. & St. L. Ry. v. Backus, 154 U.S. 421 (1894).
422 Wallace v. Hines, 253 U.S. 66 (1920). For example, the ratio of track mileage within the taxing State to total track mileage cannot be employed in evaluating that portion of total railway property found in the State when the cost of the lines in the taxing State was much less than in other States and the most valuable terminals of the railroad were located in other States. See also Fargo v. Hart, 193 U.S. 490 (1904); Union Tank Line Co. v. Wright, 249 U.S. 275 (1919).
423 Great Northern Ry. v. Minnesota, 278 U.S. 503 (1929). If a tax reaches only revenues derived from local operations, the fact that the apportionment formula does not result in mathematical exactitude is not a constitutional defect. Illinois Cent. R.R. v. Minnesota, 309 U.S. 157 (1940).