Special assessments are, properly speaking, taxes, and yet they are of so peculiar a character that the courts have not infrequently refused to bring them within the meaning of the term "tax." Thus where certain corporations or pieces of property have been by law exempted from taxation, they have, nevertheless, been held subject to special assessments.6 Again, where state Constitutions have provided that taxation shall be equal and uniform, or that all property shall be taxed according to its value, the courts have nevertheless held that special assessments for local improvements may be levied and assessed according to the front-foot rule or by a standard other than that of value.
"A local assessment can only be levied on land, it cannot, as a tax can, be made a personal liability of the taxpayer; it is an assessment on the thing supposed to be benefited. A tax is levied upon the whole state or a known political subdivision as a county or town. A local assessment is levied upon property situated in a district created for the express purpose of the levy and possessing no other function or even existence than to be the thing upon which the lew is made. A tax is a continuing burden and must be collected at short intervals for all time and without it government cannot exist; a local assessment is exceptional both as to time and locality, it is brought into being for a particular occasion and to accomplish a particular purpose and dies with the passing of the occasion and the accomplishment of the purpose. A tax is levied, collected, and administered by a public agency, elected by and responsibile to the community upon which it is imposed; a local assessment is made by an authority ab extra. Yet it is like a tax in that it is imposed under an authority derived from the legislature, and is an enforced contribution to the public welfare, and its payment may be enforced by the summary method allowed for the collection of taxes. It is like a tax in that it must be levied for a public purpose and must be apportioned by some reasonable rule among those upon whose property it is levied. It is unlike a tax in that the proceeds of the assessment must be expended in an improvement from which a benefit clearly exceptive and plainly perceived must inure to the property upon which it is imposed." 7
6 Lefevre v. Detroit. 2 Mich. 586; III. Cent. R. Co. v. Decatur, 126 III. 92. See Mich. Law Review, II, 455.