The problem of suitable and justtaxation is one which is forever demanding solution, butnever solved. Adam Smith gave to the world certain rules which should governin taxation, the first of which was that "The subjects of every state ought to contribute towards the support of the government as nearly as possible in proportion to their respective abilities - that is, in proportion to the revenue which they respectively enjoy under the protection of the state." While most writers on political economy have been disposed to accept this as a sound and just rule, some have objected to it that it puts out of view the fact that government protects persons as well as property, and that, if the burdens of government should be proportional to what is protected by jt, then persons should be taxed, not only in respect to the revenue they enjoy, but also, regardless of revenue, in return for the protection they receive as persons. This is plausible, but the practical difficulties in its application are numerous. One of these is the impossibility of estimating the comparative value of protection to one's person and to his property. Given $io,ooo to be collected as taxes from a hundred persons, one-half of whom receive an aggregate revenue of $ioo,ooo, while the others have no revenue at all; shall we say that the life and liberty of a man shall be set over against an income of $i,ooo, so that, while taxing the income 5 per cent., the poll-tax shall be $50? Such a rating would be perfectly arbitrary, because elements of comparison are entirely wanting; but, while we should probably agree that the relative rating of protection to the person was ridiculously low as compared with the rating of property, we should probably also agree that it would be impossible to collect such poll-taxes from persons who had no taxable incomes. Again, when the value of protection to the person is in question, some writers insist that this is greatest to those who are physically or mentally weak and feeble, and who, in the absence of government, would be least able to protect themselves; and, consequently, must become the prey of the more vigorous and strong, and probably fall into a condition of slavery. The proportionate tax, say these writers, would, consequently, be largest upon the weak and feeble.
Cooley, Thomas M. "Principles That Should Govern in the Framing of Tax Laws." Southern L. Rev. 4 (1878): 180-97.