after stating the case as above, delivered the opinion of the court.
The appellants — that is to say, William Russell Allen and others —who will be hereafter termed the “defendants,” contend that the city of Davenport was not entitled to a decree charging their property, as it was charged, with a lien for the cost of paving and curbing the street in controversy, because it was adjudged by the Supreme Court of Iowa in the suit brought by them against the city to enjoin the prosecution of the work that it was done under color of a contract which the city had no power to make; also because it was adjudged in the same case that the contract under which the street was improved would not support an assessment against the defendants’ property for the cost of the work, and that the assessment which was in fact made on February 3, 1897, was utterly void, and of no effect. It is a fact which cannot be gainsaid that the Supreme Court of Iowa did hold that the contract between the city and the Flick & Johnson Construction Company was so utterly void that it did not impose a liability upon the city to pay the cost of the improvement which it had attempted to authorize, and that, in view of the invalidity of the contract, the city was powerless to levy an assessment against abutting property owners to reimburse itself for the cost of the work. In the *214present proceeding, therefore, the city is in the attitude of seeking to compel the defendants to refund a sum of money which it has expended, but was under no legal obligation to' expend. The theory of the city seems to be that, although the work was done under a void contract, which did not impose a liability on the city to pay for it, yet, as the doing of the work was probably beneficial to the defendants, and may have enhanced the value of their property to some extent, they may be compelled, in what is practically an action of assumpsit, to pay its reasonable value. This is tantamount to saying that a property owner in a city may be compelled to pay the cost of any street improvement which the city sees fit to make, to the extent that he is benefited thereby, irrespective of the question whether the municipality has pursued the forms of law and exercised its power to make the improvement in the prescribed way. Indeed, as we understand counsel for the city, it is broadly claimed that by virtue of sections 478 and 479 of the Iowa Code of 1873 (quoted above in the statement) a recovery may be had or a charge enforced against a property owner for a street improvement notwithstanding any failure on the part of the municipality to observe the forms of law in the exercise of its charter powers, and that to warrant a recovery in such cases the court need only be satisfied that the work has been done or materials furnished for a street improvement which would have been chargeable against the property owner if the municipality had exercised its powers in the right way. We have not been able to conclude that this is a reasonable construction of the two sections of the Iowa Code, or a construction which has been definitely approved by the courts of that state. It is obvious that, if it be the true construction of the two sections of the Code in question, then municipalities in the state of Iowa, in the matter of making street improvements, have been freed from all restraints that are imposed by their charters for the protection of property owners. According to the view contended for, if a municipality has a general power to grade and pave streets it may ignore any provision regulating the exercise of the power which it sees fit to ignore, since its failure to act in the prescribed way will be deemed merely an informality, or an irregularity, or a defect in procedure, which in no wise relieves property owners of their liability to pay the cost of the improvement. We naturally shrink from a construction of the statute which entails such consequences; nor do we think that there is anything in the language of the statute which requires such a construction. Section 478 deals in part with matters of practice. It aims to simplify proceedings in suits to enforce assessments for street improvements by providing that it “shall be sufficient to declare generally for work and labor done” without pleading in detail all the antecedent action that has been taken by the municipality to create the charge. This provision, however, that it shall be sufficient to declare for work and labor done cannot be understood as absolving the pleader from the obligation to prove on the trial that the municipality has in fact taken substantially all the steps which the law requires it to take to create a valid charge against the owners of abutting property. The statute deals with the subject of pleading, and, while it abbreviates the complaint in this class o£ cases, it does not lessen the measure of proof-that is necessary to estab*215lish a liability. Section 479 appears to have been enacted to prevent property owners from taking'advantage of defenses that are purely technical in suits brought against them to enforce assessments for street improvements, when the evidence shows that the power to make such improvements has been exercised by the municipality in substantial conformity with law. The Legislature foresaw that, when a municipality undertook to exercise its power to improve streets at the expense of abutting property owners, it might happen that the municipality, through oversight, would neglect to do every act in the precise form prescribed by its charter and ordinances, or to do it in the regular way, or at the right moment, and that there might be some defect of this nature in the course of procedure which would be in no wise prejudicial to the property owner. It accordingly declared that mere informalities or defects in the course of procedure where the municipality had exercised its powers in substantial conformity with law should not serve to prevent the enforcement of a charge against abutting property for its proportion of the cost of the improvement. Remedial legislation of this character, which is intended to deprive a taxpayer of technical defenses grounded on the fact that everything has not been done in the right form, or in the prescribed order, although there has been a substantial compliance with the law, is quite common, and also very wholesome. But laws of this character should not be so interpreted as to deprive the property owner of his right to insist that his property shall not be charged with the cost of improving streets and making other improvements, unless there has been a substantial compliance with those provisions of the law that were enacted for his benefit and for his protection. It is an elementary doctrine that municipalities have no power to impose burdens on property for street and other local improvements unless the power to impose such burdens has been expressly conferred upon them by the Legislature. It is an exercise of the power of taxation, and this power belongs to the state, and is one of the highest attributes of sovereignty. When, therefore, the power is delegated to a municipal corporation, and laws are enacted prescribing the purposes for which it may be used, and the mode and manner of its exercise, these provisions of the law are mandatory, and should be carefully observed. French v. Edwards, 13 Wall. 506, 20 L. Ed. 702; Lyon v. Alley, 130 U. S. 177, 9 Sup. Ct. 480, 32 L. Ed. 899; Hager v. City of Burlington, 42 Iowa, 661; Warren v. Mayor, etc., of the City of Boston (Mass.) 62 N. E. 951; McCoy v. Briant, 53 Cal. 247; 2 Smith’s Modern Law of Municipal Corporations, § 1242; Cooley on Taxation, page 656. A municipality cannot enforce a charge against the property of one of its citizens for local improvements unless it is able to show that it has proceeded according to law by taking substantially all of the initial steps which the law prescribes as necessary to create the charge. If it fails to do something which the law intended to be done for the protection of the citizen, and to prevent the imposition of an undue burden upon his property, an omission of this sort ought not to be looked upon as a mere informality or irregularity in the course of procedure, but should rather be regarded as a failure to do some necessary act which rendered its subsequent act's invalid and the charge unenforceable.
*216It is obvious, we think, that the city of Davenport had no power to assess a special tax against the property of these defendants for the improvement of the street or road which it resolved to improve, unless the work in question was done in pursuance of a contract. Sections 2 and 3 of chapter 7 of the Acts of the Twenty-Fifth General Assembly, supra, under which the city seems to have proceeded, expressly require that such work shall be done by contract, to be let to the lowest bidder after due notice. A general ordinance of the city that was in force when the work in question was undertaken contained provisions to the same effect, namely, that such work should “be done according to plans and specifications approved by the council under contract,” and that a notice should be published for not less than 10 days inviting proposals for doing the work. Moreover, the city itself proceeded on the theory that such work could only be done in pursuance of a contract, and it accordingly invited proposals, and entered into a contract for the doing of the work with the Flick & Johnson Construction Company. This contract, however, was one in excess of the power of the city to either make or perform, and the attention of the city and the contractor was immediately called to the fact of its invalidity before any of the work was done. The city saw fit to ignore the suggestion that the contract was void. It proceeded with the work, and paid for it, and now calls upon the defendants for reimbursement; its claim being, apparently, that, while the contract was utterly void as between itself and the contractor, it was nevertheless valid in so far as the defendants are concerned, or at least that they should not be permitted to take advantage of its invalidity.
We have not been able to adopt that view of the case. The con- • tract in question, whereby the city assumed an obligation to pay the entire cost of the work, and to pay it in money, was made in open violation of the Constitution of the state of Iowa, as the Supreme Court of that state has held (vide Allen v. City of Davenport, 107 Iowa, 90, 77 N. W. 532). The contract, being in excess of the power of the city, was not merely voidable, but absolutely void, creating no obligation that could be enforced as against either of the contracting parties. Central Transportation Co. v. Pullman Palace Car Co., 139 U. S. 24, 48, 59, 11 Sup. Ct. 478, 35 L. Ed. 55; California Bank v. Kennedy, 167 U. S. 362, 367, 17 Sup. Ct. 831, 42 L. Ed. 198; De La Vergne Co. v. German Savings Institution, 175 U. S. 40, 59, 20 Sup. Ct. 20, 44 L. Ed. 65. A void contract is in fact no contract, since an instrument of that nature does not alter the relations previously existing between the contracting parties, nor will it serve as the foundation of any right. When such a void agreement is signed, the situation of the parties thereto remains the same as before it was executed. Now, it must be assumed, we think, that when the act to which we have heretofore referred declares that when a city resolves to improve one of its streets it shall enter into a contract for the doing of the work as a condition precedent to making the cost of the work a charge upon abutting property, it means a valid contract; that is to say, one which the *217city can enforce, if need be, both for its own protection and for the protection of property owners. Persons whose property is liable to be charged for the cost of a street improvement have as much interest in the contract under which the work is done as the cit3r itself, and the right to insist that it shall be entered into in such manner that it may be’ enforced against the contractor. We fail to perceive, therefore, how the mere signing of an agreement, which, as between the contracting parties, was utterly void, can be accepted as a sufficient compliance with the provisions of the statute that the work of improving streets must be done by contract or how such an agreement can serve as the foundation of a charge against the defendants’ property, when it failed to create any rights as against the city.
In behalf of the city it is contended, however, that the Supreme Court of Iowa has taken a different view of this question, and has held that in virtue of section 479 of the Code of Iowa of 1873 a charge against abutting property for street improvements may be enforced although the proceedings taken to create the charge disclosed as grave defects as the proceedings in the case at bar. The decisions to which our attention has been particularly invited, and on which the lower court seems to have relied, are the following: City of Burlington v. Quick et al., 47 Iowa, 222; Dittoe v. City of Davenport, 74 Iowa, 66, 36 N. W. 895; City of Muscatine v. Chicago, Rock Island & Pacific Ry. Co., 79 Iowa, 645, 44 N. W. 909; Tuttle v. Polk & Hubbell, 92 Iowa, 433, 60 N. W. 733; Ottumwa B. & C. Co. v. Ainley, 109 Iowa, 386, 80 N. W. 510; City of Chariton v Holliday, 60 Iowa, 391, 14 N. W. 775; Fort Dodge Elec. Eight & Power Co. v. City of Fort Dodge (Iowa) 89 N. W. 7.
In the first of these cases — City of Burlington v. Quick — it appears that the city council had ordered the improvement of a street and the levy of a special tax upon abutting property owners, and had directed the auditor of the city to ascertain the amount of such tax by dividing the whole expense by the number of front feet abutting the improvement, the result to be the assessment upon each front foot of property. It was claimed in that case, as it seems, that by an ordinance of the city the council was required to levy and assess the tax, and that the assessment was invalid because it had been made by the auditor instead of the council. It was held, however, that the duty performed by the auditor in the matter of apportioning the tax was merely clerical, and that, as the council had ordered both the levy and the assessment, and had directed the auditor how to apportion it, and as the apportionment had also been made in accordance with the provisions of a general ordinance on the subject, the assessment was in fact made by the council, and that the property owner had no right to complain.
The case of- Dittoe v. City of Davenport was one in which the plaintiff had paid a tax for the construction of a sewer under protest, and brought an action against the city to recover the sum paid. He claimed that the charge which he had paid was illegal, for the reason that the resolution of the city council assessing it did not definitely describe the sewer, nor fix the gross amount of *218the cost of the sewer, nor the amount per square foot to be assessed against adjacent property, as it should have done. He also claimed that no notice of the assessment had been given, and that he had had no opportunity to be heard in regard thereto. It appeared, however, that the street through which the sewer was to be constructed and its terminal points were described in the resolution ; that the resolution assessing the tax also directed that it be assessed and levied on each lot, part of lot, or tract of ground in the sum and to the amounts shown by the plat of the city engineer; and it was admitted that this plat, to which reference was made, showed the amount to be assessed per square foot, the number of square feet in each tract, and the total assessment as respects each tract subject to be assessed for the sewer. It was accordingly held that the resolution of the council, in effect, adopted so much of the plat of the engineer as was referred to therein, and thereby furnished the means of obtaining precise knowledge of the amount of the tax assessed against each tract of land and each individual,,and the total cost of the sewer, and that this was a substantial compliance with the law, and a sufficient compliance to sustain the validity of the charge. With reference to the other objection — that the taxpayer had been given no opportunity to be heard with reference to the assessment — the court said, in substance, that by demurring to the answer which was filed by the city, the plaintiff had admitted facts showing that the cost of the sewer had been assessed in all respects in conformity with law against each tract of land; that it appeared also that, if the plaintiff had been given an opportunity to be heard, it would have been of no advantage to him; and that the defect in the proceedings of which he complained did not affect the substantial merits of the case, nor entitle him to recover from the city the amount of the assessment which he had already paid.
In the case of Ottumwa B. & C. Co. v. Ainley, which was a proceeding to enforce a tax for a street improvement, it appeared that the city had advertised for proposals for the doing of the work, and had specified therein that the contractor should accept certificates to be issued by the city in full payment for the work and labor done in making the improvement. Only one bid for the doing of the work was received, and in this bid the contractor had inserted a provision that the city should guaranty the payment of a certificate which it was to issue against certain property lying on the west side of the street. The bid containing this provision was accepted by the city. It was claimed by the taxpayer that, inasmuch as the bid which was accepted by the city contained the aforesaid provision, and the same was in conflict with the terms of the resolution inviting proposals, the contract under which the work had been done was void, and that assessments subsequently made against abutting property could not be enforced. It appeared on the trial that the property lying on the west side of the street, with respect to which the city had guarantied the payment of the certificate which might be issued against it, was property which lay below ordinary high-water mark on the bank of a river, and there*219fore belonged to the state; that the city could not charge such property with a lien for the street improvement, but was itself responsible for the assessment against such property; that, in the absence of an express guaranty with respect to the charge against that property, the city would have been liable therefor as upon an implied guaranty and that for these reasons the acceptance of the contractor’s bid with the provision contained therein with reference to a guaranty by the city did not affect the legality of the contract. The court further said that without the city’s' guaranty the cost of paving in front of the property in question would have been apportioned against other real property abutting on the improvement; that is to say, that the cost to other property owners would have been increased by the amount necessary to make the improvement in front of the tract in question; that there was nothing in the law to prevent a city, whose finances would admit of its so doing, from paying for an improvement like the one in question out of its general funds; and that at most all the case disclosed was a mere irregularity in the course of the proceedings which was not jurisdictional, but might be disregarded under section 479 of the Code of 1873. It is a notable fact that this case proceeds upon the assumption that, if the contract between the city and the contractor was in fact invalid, no charge for doing the work could be enforced against abutting property owners.
In the case of the City of Chariton v. Holliday, supra, It appeared that a general ordinance of the city, which was in force, provided the mode of assessing the cost of constructing sidewalks, and that a resolution had been adopted directing the building of a particular sidewalk, which resolution did not expressly provide the mode of assessment. It was held that the omission to prescribe the method of assessment in the resolution directing the construction of a particular sidewalk was a mere irregularity in view of the fact that a proper method of assessment was prescribed by the general ordinance, and that that method of assessment had been followed. In this case the Supreme Court of Iowa said, however, that “the irregularity or defect which, under this section (section 479 of the Code), can be disregarded, must, we think, be a mere error or omission to do something which in no manner affects the jurisdiction of the city.”
The other cases to which our attention is directed contain no utterances, so far as we have been able to ascertain, that are pertinent to the case in hand. Considering the questions actually adjudicated in the cases to which we have referred, we are of opinion that they would not warrant us in holding that the city of Davenport, by virtue of the provisions contained in sections 478 and 479 of the Code of 1873, as construed by the Supreme Court of the state of Iowa, can enforce a charge against abutting property owners for a street improvement, where the work of improving a street is done under an utterly void contract. We feel constrained to hold that the making of a valid contract for the doing of such work is a jurisdictional prerequisite to the establishment of a charge against abutting property for the cost of the improvement. The laws of *220the state, as well as the ordinances of the city to which we havfe already referred, clearly contemplate that such work shall always be done in pursuance of a contract, and no step in the course of the proceeding to charge abutting property owners with the cost of such work would seem to be more necessary for their protection.
The defendants further contend that, irrespective of other defenses, the decree which was rendered in the suit which they formerly brought against the city of Davenport to enjoin the prosecution of the work and the collection of the assessment of February 3, 1897, operates as a bar to this action. This leads us to inquire what issue or issues were involved in the former action. As we view the bill of complaint in that case, the defendants challenged the right of the city to charge the cost of the proposed improvement against them or their property upon any ground, provided the work was proceeded with under the contract that had been entered into with the Flick & Johnson Construction Company. They asserted not only that the contract with that company was one which the city had no power to make, and that it was on that account void, but, as a corollary from his proposition, that, if the work was done under that contract, the doing of the work would not operate to create a lien against their property, or a personal liability against them. They accordingly prayed that the prosecution of the work might be enjoined to prevent the possible assertion of a lien against their property for its cost. The bill was in its essence one to prevent a cloud being cast on their title. On no other ground than that of avoiding a cloud upon the title to their property which might be created if the work was done as proposed were they entitled to seek relief in a court of equity. It is true that the contention in the former suit was principally with reference to the validity of the contract with the Flick & Johnson Construction Company, but the decision of that question was only important, so far as the defendants were concerned, in that it determined the other question in which they were vitally interested — whether, if the work was done under that contract, the cost thereof could be charged as a lien against their property. We feel constrained to hold, therefore, that the fundamental issue which was presented by the former action was whether the defendants’ property could be charged with the cost of the improvement if the city proceeded with it in the proposed' manner. This issue was decided in favor of the defendants and adversely to the city.
Such being the broad issue that was tendered by the bill in the former case, why is it not true that the decree which was rendered in that case is a bar to the present suit? Counsel for the city say that it did not urge in that case the right to recover the cost of the improvement in virtue of sections 478 and 479 of the Code of Iowa of 1873, and that its right of recovery under those sections is a question-which remains open and undetermined. But if it be true, as now contended, that, notwithstanding the invalidity of the contract in question, the city was entitled to collect a proper proportion of the cost of the-improvement out of the defendants’ property, and to have it charged with a lien therefor because the defect in the contract was a mere informality or irregularity in matters of procedure, which might be ignored, why was it not the duty of the city to have pleaded that fact *221as a defense against the relief sought in the former action? We think that, if the latter theory is sound, the city had a perfect defense to the former action, and should have pleaded it, for, if sections 478 and 479, supra, gave the city the right to collect out of the defendants’ property its proper proportion of the cost of the work, although it was not done under a valid contract, then the defendants’ bill contained no allegations entitling them to such equitable relief as was prayed for and after-wards granted, since the prosecution of the work would have created no cloud on their title of which they could well complain. No chancellor, we think, would have granted an injunction against the prosecution of the work if it had been made to appear that the action taken by the city had been so far in accordance with law that it would, in any event, be entitled to recover the cost of the work in virtue of the provisions of sections 478 and 479 of the Code.
It is a well-settled doctrine, at least in the federal courts, that a person who seeks to enforce a demand of any kind by a suit must allege all of the grounds that entitle him to the relief sought, because, if he fails to recover on one ground, the law will not permit him, after such failure, to obtain the same relief against the same party on some other ground which might have been advanced in the first action. A like rule applies to the defendant who is proceeded against. He should take advantage of all of his defenses, since the law will not allow him to test the merits of one defense, and, if defeated, interpose another. A judgment rendered against him establishes conclusively that he has no defense to the demand. The rule in question was once tersely stated by this court in the following language in the case of Board of Commissioners of Lake County v. Platt, 25 C. C. A. 87, 91, 79 Fed. 567:
“In. an action between the same parties, or those in privity with them, upon the same claim or demand, a judgment upon the merits is conclusive not only as to every matter offered, but as to every admissible matter which might have been offered to sustain or defeat the claim or demand.”
See, also, to the same effect, Cromwell v. County of Sac, 94 U. S. 351, 352; 24 L. Ed. 195; Southern Minnesota Railway Extension Co. v. St. Paul & S. C. R. Co., 5 C. C. A. 249, 55 Fed. 690; Beloit v. Morgan, 7 Wall. 619, 621, 622, 19 L. Ed. 205; Hubbell v. United States, 171 U. S. 203, 18 Sup. Ct. 828, 43 L. Ed. 136; Southern Pacific Railroad v. United States, 168 U. S. 1, 48, 18 Sup. Ct. 18, 42 L. Ed. 355; Hardwick v. Young (Ky.) 62 S. W. 10.
In order that a person, may be precluded from alleging certain facts as a ground of recovery or relief, it is not always necessary that they shall have been pleaded as a ground of recovery or defense in some other action between the same parties, and expressly declared to be insufficient to warrant a recovery or sustain a defense. It is sufficient if it appears that the party seeking to avail himself of such facts as a ground of recovery has had an opportunity to plead them in the former action as a' defense thereto, and that they might have been pleaded and considered as a defense to the former action. Applying this doctrine to the case in hand, we are of opinion that the decree in the former suit is a bar to a recovery in the present action. The city had an undoubted right to plead, in opposition to a recovery in the former suit, the same facts on account of which it seeks a recovery in the present action, *222and if they were in fact of such a nature as entitles it to a judgment against the defendants in the present suit for the cost of the improvement, then they would have precluded a recovery by the defendants in the former action, in that they would have shown that in that suit the defendants were not entitled to equitable relief. We conclude, therefore, that within the doctrine heretofore announced the decree in the former case estops the city from recovering against the defendants on a ground which, if it was ever tenable, might have been successfully pleaded as a defense to the former action.
The defendants, in connection with their answer, filed a cross-bill, which is in the nature of a bill of peace, wherein they pray that the city may be now enjoined from asserting any further claim against them on account of the work done and materials furnished in improving the street or road through their property, and from bringing any further actions to enforce a claim of that nature. Nothing was said concerning the cross-bill on the oral argument, and very little is said with respect to it in the brief. In view of this fact, and in view also of what has already been said concerning the right of the city to enforce the claim in question, we think that it is wholly unnecessary, and would be a work of supererogation, to grant any affirmative relief on the cross-bill.
The order of this court will be, for the reasons heretofore stated, -that the decree of the Circuit Court be, and the same is hereby, reversed and annulled, and that the bill which was filed by the city be., and the same is hereby, dismissed, at its cost.
The appeal taken by the city in case No. 1,990 is also dismissed, at its cost.