delivered the opinion of the court.

This is an attempt to reverse a judgment confirming an assessment on certain leaseholds of tide lands. The leases were executed by the State in 1899. Subsequent statutes of 1905 and 1907 respectively, authorized the assessment of such leaseholds for local improvements specially benefiting them, and the inclusion of them within local improvement districts by cities of the first class. The City of Seattle made a plank roadway, created an improvement district, levied an assessment which failed, Coast Land Co. v. Seattle, 52 Washington, 380, and then in due form levied the reassessment that is in question here. The plaintiffs in error argue that the leases contained an implied covenant for quiet enjoyment and that the subsequent laws that authorized the assessment impair their constitutional rights. Art. I, § 10. Amendment XIV, § 1. The Supreme Court of Washington, admitting the general rule as to leases, held that so far a.s concerns taxation, it did not apply to leases made by the State. 64 Washington, 102.

The concession of the court was that in private contracts “in the absence of a covenant or condition to the contrary, it is an implied covenant in every lease that the lessor shaíl pay all taxes and assessments levied on the leased land during the term.” Stated in this form, the rule appears to be a rule of policy to which special considerations may set a limit. But it might be suggested that if the State should expressly covenant against such[*688] assessments it could not impair the obligation of its contract by a subsequent law. The words used in these leases are ‘lease, demise and let,’ and from Spencer’s Case, 5 Co. Rep. 16a, 17a, down to the present day these words have been said to imply a covenant. 1 Wms. Saund. 322, n. 2. Mostyn v. West Mostyn Coal & Iron Co., 1 C. P. D. 145, 152. Mershon v. Williams, 63 N. J. L. 398, 406. Words express whatever meaning convention has attached to them, and so it may be argued that the State has covenanted against this tax in express terms.

Nevertheless it is obvious that the supposed meaning was not reached by simple interpretation. There is no suggestion of warranty, in dedi or demisi by any usage of speech alone. The warranty was what Lord Coke called a warranty in law, Co. Litt. 384a, an institution, not depending upon an expression of intent, not arising because the words mean warrant, but imposed from without by the law. In Butler’s note to this page the lessor’s obligation is put as reciprocal to the tenant’s obligation to pay rent, (compare 5 Co. Rep. 17a), just as the warranty in dedi in some cases was a consequence of tenure. One may wonder whether in fact the warranty incident to a sale in early law before the machinery of implied contracts was thought of (Glanv. VII, c. 2; X, c. 15; Lex. Sal. c. 47; 1 Löning, Vertragsbruch, 103; 2 Inst. 274, 275), was not given a scholastic turn, extended, limited and embodied in sacramental words — whether Glanville’s Donatores, grantors, did not suggest the special effect of dedi in the Statute de Bigamis as interpreted by Lord Coke. (The Statute itself says that the feoffor is held ratione doni proprii. 4 Ed. I., c. 6.) But whatever may be the history, it is plain, as we have said, that the rule is not the result of interpretation but of doctrine; and hence it is that very commonly the rule is stated as expressing the general operation of a lease and not as depending upon the use of a particular word. 64 Washington, 102, 104. J. W. Perry [*689] Co. v. Norfolk, 220 U. S. 472, 477. Duncklee v. Webber, 151 Massachusetts, 408, 411, and cases cited in 24 Cyc. 1057; 18 Am. & Eng. Encyc. of Law, 2d ed. 650. . It has come back to what it started as being, a construction of the law; and since, notwithstanding its age, the special effect of demisi has not entered into speech so far as to reach popular understanding, the rule still may be construed as extending no further than reason dictates. Indeed warranties in law always have been dealt with on this principle. See e. g. Brett v. Cumberland, Cro. Jac. 521, 523. Therefore we may consider the question before us on the footing upon which it was discussed by the Supreme Court of the State.

The question is, then, whether our duty requires us to overthrow a decision that the policy of the state law excludes a constructive obligation to indemnify against the exercise of the sovereign power of taxation from leases by the State. Put in this form, it is not hard to answer. When the law creates an obligation outside of the expressed intent of the parties, it must consider all the circumstances, and the effect with reference to them. In ordinary cases the whole property is taxed and which party shall bear the burden is not a matter of public concern. But when the State makes the lease, the supposed obligation would be an obligation not to tax — a restriction of public import not lightly to be imposed. Providence Bank v. Billings, 4 Pet. 514, 561. Wells v. Savannah, 181 U. S. 531, 539, 540. St. Louis v. United Railways Co., 210 U. S. 266, 273, 274. J. W. Perry Co. v. Norfolk, 220 U. S. 472, 480. It is urged that to deny the State’s obligation discriminates unconstitutionally against this class of lessees, since all others are free from the burden. But that is not true. Whether landlord or tenant shall pay a tax is a matter of private arrangement, and the practice one way or the other has no bearing on the matter. The argument from inequality really works the other way. If these leaseholds are not[*690] taxable, they are a favored class of property; for ordinarily leaseholds are taxed even if they are lumped and included in the value of the fee. When an interest in land, whether freehold or for years is severed from the public domain and put into private hands, the natural implication is that it goes there with the ordinary incidents of private property and therefore is subject to being taxed. See New York ex rel. Metropolitan Street Ry. Co. v. New York State Board of Tax Commissioners, 199 U. S. 1, 38.

The plaintiffs in error think that thus far there has been a failure to understand their contention that these assessments aré against the land, and therefore are met by the supposed contract of the State, that the lessees should have the land free of all charges. The court below appears to us to have decided in direct' response to that argument that the contract of the State did not go so far, and we are of opinion that we ought not to pronounce the decision wrong. There was some subsidiary discussion of the meaning and operation of the Statutes, but upon those matters we do not go behind the judgment of the Supreme Court of the State. '

Judgment affirmed.