(after stating the facts). The bill attacks the validity of the Kentucky revenue law of November, 1892, and seeks relief against its enforcement on the ground that, in its application to the complainant bank, it violates that clause of the federal constitution which forbids a state to pass a law impairing the obligation of a contract. The case is therefore one arising under the constitution of the United States, and, as it involves more than f2,000, it is within the jurisdiction of this court. Do the facts stated in the bill bring it within the equity jurisdiction of the court? It is well settled that in the federal courts an action in equity will not lie to restrain the collection of a tax on the sole ground that it is illegal and void, and independently of every other consideration. See Rich v. Braxton, 158 U. S. 375, 405, 15 Sup. Ct. 1006. It must appear from the special circumstances averred that there is no adequate remedy at law, and that there is some recognized ground for equity jurisdiction, such as that the enforcement of the tax would lead to a multiplicity of suits or produce irreparable injury. Ogden City v. Armstrong, 168 U. S. 224, 236, 18 Sup. Ct. 98; Express Co. v. Seibert, 142 U. S. 339, 12 Sup. Ct. 250; Allen v. Car Co., 139 U. S. 658, 661, 11 Sup. Ct. 682; Shelton v. Platt, 139 U. S. 591, 11 Sup. Ct. 646; Railway Co. v. Cheyenne, 113 U. S. 516, 525, 5 Sup. Ct. 601; Hannewinkle v. Georgetown, 15 Wall. 547; Dows v. City of Chicago, 11 Wall. 108. What are the remedies at law which the complainant has? If the collecting officers proceed to collect the tax by distraint, the bank may, under the duress of the threatened trespass, pay the taxes alleged to be illegal, and then sue the city of Louisville, the county of Franklin, and the city of Frankfort to recover them back. Railroad Co. v. Commissioners, 98 U. S. 541. It is to be observed, however, that no such action will lie except upon payment under duress. The bank could not simply pay under protest, and sue to recover back. Such a payment would be voluntary. There is no statute of Kentucky providing such a remedy, as there was in Tennessee in the case of Shelton v. Platt. The remedy of paying and suing to recover back in Kentucky exists only when the collecting officer resorts to distraint. But the collecting officers are not obliged to collect the taxes by distraint; they may resort to a simple suit at law for them. In that case the bank may defend on the ground of the invalidity of the law under which the taxes have been assessed. This remedy, except where the taxes are a cloud upon real estate, would ordinarily be adequate; but, under the provisions of the revenue law of November, 1892, we do not think it is. By that law, the bank, on failing to pay the taxes assessed, according to its provisions, within 30 days after notice from the collecting officer, is subjected to a penalty of 10 per cent., and to a fine of $50 a day for every day of the delinquency, to be enforced by indictment or by civil action. It follows that the remedy of defending a suit at law for taxes under this revenue act is attended with the risk of being compelled to pay $50 a day for every day of the time necessarily consumed in the reasonable litigation of the question of the validity of the tax. By bill in equity, the bank may enjoin the assessment, *391and ponding tbe litigation, however long the delay, no lines or penalties can accrue 'against the unsuccessful litigant, because, by the terms of the act, they do not begin to accrue until 30 days after notice to pay lias been given by the collecting officer. It is manifest that the remedy at law by defending a tax suit in such cases is attended with a great and oppressive burden of risk, which is absent in an action in equity. The remedy at law is therefore entirely inadequate. Smyth v. Ames, 169 U. S. 466, 518, 18 Sup. Co. 418; Express Co. v. Seibert, 44 Fed. 315. It is no answer to say that the payment of the tax and the action to recover it back constitute an adequate remedy, because no such action will lie, as already explained, unless there is a distraint, actual or threatened, and the collecting officer, by not distraining, may wholly deprive the taxpayer of this remedy. Indeed, the counsel for the city of Louisville vigorously contends that the collecting officer in that city has no power to distrain for bank taxes. However this may be, it would seem clear that a court of equity will not withhold relief from a suitor merely because he may have an adequate remedy at law if his adversary chooses to give it to him. The remedy at law cannot be adequate if its adequacy depends upon the will of the opposing party. To refuse relief in equity upon the ground that there is a remedy at law, it must appear that the remedy at law is “as practical and efficient to the ends of justice and its prompt administration as the remedy in equity.” Boyce v. Grundy, 3 Pet. 210, 215; Sullivan v. Railroad Co., 94 U. S. 806, 811. And the application of the rule depends upon the circumstances of each case. Watson v. Sutherland, 5 Wall. 74, 79.
The practice of the state courts of Kentucky in issuing injunctions against the collection of taxes cannot, of course, be a controlling consideration in determining the limits of the equity jurisdiction in the federal courts in such cases; for it is settled that if a case, “in its essence, be one cognizable in equity, the plaintiff (the required value being in dispute) may invoke the equity powers of the proper circuit court of the United States whenever jurisdiction attaches by reason of diverse citizenship or upon any other ground of federal jurisdiction.” Smyth v. Ames, 169 U. S. 466, 516, 18 Sup. Ct. 418. But it is worthy of note that the court of appeals of Kentucky has held that, in the absence of a statute allowing an action to recover back from the state taxes illegally collected, the remedy by injunction is the only adequate one.
In Gates v. Barnett, 79 Ky. 295, 296, the court, in a suit to enjoin a distraint upon certain tobacco for the collection of taxes, said:
“The right to have an injunction to restrain tlio collection of an illegal iax has been so long recognized and acted upon in this state that it is unnecessary to stop to incniire upon what ground that jurisdiction is exercised by courts of equity. The jurisdiction in this case, however, may be placed upon the ground of the inadequacy of the remedy at law. The officer, acting in good faith and under color of right, is justified by his process, and is not'liable as a trespasser: and, as a suit would not lie against the state directly, the only complete remedy is by injunction.”
It is by no means clear that distraints or threatened distraints against a bank, in view of the character of its business, may not *392involve such, serious detriment to its business, and incidentally to the public, as to justify equitable intervention.
In the case of Lenawee Co. Sav. Bank v. City of Adrian, 66 Mich. 273, 276, 33 N. W. 304, 306, a levy upon and seizure of the bank furniture and fixtures was in progress when an injunction was issued. Mr. Justice Campbell, speaking for the court, said:
“No point was made in the pleadings or on the argument against the jurisdiction of equity in this case. As the hank was not liable to taxation at all on its personal property, and the levy was made in such a way as to directly interfere with its Business, the case comes within the analogies of the cases represented by Osborn v. Bank, 9 Wheat, 738, from which it cannot be readily distinguished. The court below does not appear to have doubted the jurisdiction, although deciding in favor of defendants on the merits.”
In Railway Co. v. Cheyenne, 113 U. S. 516, 525, 5 Sup. Ct. 601, 605, Mr. Justice Bradley said:
■“It cannot be denied that bills in equity to restrain the collection of taxes illegally imposed have been frequently sustained. But it is well settled that there ought to be some equitable ground for relief besides the mere illegality of the tax; for it must be presumed that the law furnishes a remedy for illegal taxation. It often happens, however, that the case is such that the person illegally taxed would suffer irremediable damage or be subject to vexatious litigation if he were compelled to resort to his legal remedy alone. For example, if the legal remedy consisted only of an action to recover back the money after it had been collected by distress and sale of the taxpayer's lands, the loss of his freehold by means of a tax sale would be a mischief hard to be remedied.”
The interference with the business of a bank and the injury to its credit caused by a distress against its personal property would seem to be a mischief equally hard to be remedied by a mere suit to recover the money back when thus collected.
If it were necessary, we do not think that it would be difficult to sustain the jurisdiction here on the ground that it will prevent a multiplicity of suits. The complainant is seeking to enforce a privilege or exemption which it avers has already been established by the decision of the highest court of the state. To how much more litigation is it to be subjected? Can it not have a remedy in equity against future attempts to invade the privilege already decided to belong to it?
In Osborn v. Bank, 9 Wheat. 738, 842, Chief Justice Marshall said:
“The single act of levying tbe tax, in the first instance, is the cause of an ac ■ tion at law; but that affords a remedy only for the single act, and is not equal to the remedy in chancery, which prevents its repetition and protects the privilege.”
See, also, Morris Canal & Banking Co. v. Mayor, etc., of Jersey City, 12 N. J. Eq. 227; High, Inj. § 530.
In addition to the suits for future taxes, there is also danger of harassing suits for fines and penalties which the law permits to be brought for each day’s delay in the payment of the taxes after they have been demanded. We have no doubt that if the complainant shows that the act of November, 1892, violates an exemption secured to it by contract, it may have equitable relief.
*393The second question in the case is that raised by the averment of former adjudication. The case of City of New Orleans v. Citizens’ Bank of Louisiana, 167 U. S. 371, 17 Sup. Ct. 905. it is impossible to distinguish from that before us upon the point of res judicata. The Citizens’ Bank, in New Orleans, was exempted from taxation by an act of tire legislature of Louisiana, of January 30, 1836. Extern sion of its charter was granted and accepted, and the question was mooted whether the exemption from taxation continued after extension. The bank brought suit in the district court of New Orleans ro enjoin the collection of a tax against it, on the ground that it had, by legislative contract, exemption from the same. The district court sustained the claim, and enjoined the collection of the tax. A second suit, brought to enjoin another year’s taxes, resulted in a similar judgment. Some years later, the city of New Orleans having attempted to collect a tax for a subsequent year, in violation of the exemption, the bank filed its bill in equity in the circuit court of the United States for the Eastern district of Louisiana, to enjoin the officers of the state and the city from proceeding to collect the tax, and set forth the former adjudication as a conclusive estoppel upon the defendants as to the point of the previous litigation, namely, that there was a contract between the state and the bank forbidding such taxation. The causes of action were not the same in the case brought in the federal court and the cases adjudged in the state courts, because they involved taxes for different years; but the thing adjudged, to wit, the existence and binding effect of the contract for the exemption from the particular taxation, was the same. The supreme court of the United States in this case held that the city of New Orleans and the state taxing authorities were conclusively estopped by the judgments in the state courts from asserting any right to collect the tax in violation of the contract ad judged to exist in the prior litigation, and held that, the contract having been thus established, the hank was entitled to relief from a violation of that contract by any acts of the state officials acting-under the authority of state legislation. It had theretofore been doubted in some courts whether a judgment in a suit for taxes could be held to be an estoppel against a state or any agency of the state for the collection of taxes in a suit for taxes subsequently accruing, but the question is now definitely settled. Mr. Justice White, in delivering the judgment of the court, in a most elaborate opinion, said:
“The proposition that, because a suit for a tax of one year is a. different demand from the suit for a tax for another, therefore res judicata cannot apply, whilst admitting in form the principle of the thing adjudged, in reality substantially denies and destroys it. The estoppel resulting from the thing adjudged does not depend upon whether there is the same demand in both cases, but exists, oven though there be different demands, when the question upon which the recovery of the second demand depends has under identical circumstances and conditions been previously concluded by a judgment between the parties or their privies. This is the elemental rule, stated in the text-books, and enforced by many decisions of this court. * * S: It follows, then, that the mere fact that the demand in this case is for a tax for one year, and the demands in the adjudged cases were for taxes for other years, does not prevent the operation of the thing adjudged if, in the prior cases, the *394question of exemption was necessarily presented and determined upon identically the same facts upon which the right of exemption is now claimed.”
In the case before us there can be no question, from the statement of facts and an examination of the records in previous cases as set forth therein, that the question which was adjudged in them was the identical question presented in the same way and for the same purpose as in the case at bar, to wit, whether there was a contract between the bank and the state which forbade Um imposition of higher taxes than those imposed under the Hewitt act. It was distinctly adjudged, in behalf of the complainant against Franklin county and the city of Frankfort, by the court of appeals, by the decision rendered in 1895, and by a mandate issued from that court to the Franklin circuit court, that such a contract in fact existed, and rendered null and void the provisions of the revenue act of November 11, 1892, under which the defendants now seek to impose taxes upon the complainant.
It is vigorously pressed upon us, however, that the judgment in the prohibition suit cannot be relied upon by the complainant bank to establish the existence of a contract of exemption between it and the city of Louisville, because there is nothing in the record to show that the issue made by the demurrer to the petition in that suit was the existence of such an exemption and its violation. Neither the mandate of the court of appeals nor the judgment of the Jefferson court states the ground for holding the ordinance void. It is said that some 30 days before the decision of the prohibition case by the court of appeals that court, in Levi v. City of Louisville. 97 Ky. 394, 30 S. W. 973, held that the city of Louisville had no power under the constitution to substitute a license tax for ad valorem tax on personal property, and that this ruling must have led to o.verruling the demurrer to the petition in the prohibition suit, because it necessarily rendered the license tax upon the banks void. The Levi Case was a suit by an owner of real estate to enjoin the collection of an ad valorem tax on his land, on the ground that the city had not imposed such a tax on personalty, but had substituted therefor a license tax upon it, and so had discriminated in favor of personal property and against realty. The court of appeals held that it was the duty of the city to impose an ad valorem tax on personalty, and that it could only impose a license tax on a business in addition to an ad valorem tax on property. We confess we cannot see how this decision would have determined the question at issue between the complainant bank and the city of Louisville, in the prohibition suit. There was nothing in the petition for prohibition to show that the license tax was a substitute for an ad valorem tax upon the personal property of the bank. There was nothing to show that the city of Louisville had not, under the revenue act of 1892, assessed an ad valorem tax on the bank’s personalty. The license tax was graduated by a percentage, not of the bank’s personal property, but of the bank’s gross receipts, and did not therefore purport to be a taxation on its personal property. The petition was not therefore demurrable under the Levi Case. When we further consider that the sole ground stated in the petition for a prohibí *395lion was that the license tax was void, because it impaired the bank’s contract oí exemption, and so violated the constitution of the United States, and we find that this was the sole ground considered by the court of appeals in its opinion, we can have no doubt what was the point adjudged.
The case of City of New Orleans v. Citizens’ Bank of Louisiana, 167 U. S. 371, 17 Sup. Ct. 905, is relied on to support the contention that a judgment that a license tax violated the bank’s contract of exemption cannot be pleaded as res judicata in a case presenting the question whether a franchise tax violates its right of exemption. In the City of New Orleans Case the language of the exemption was: “The capital of said bank shall be exempt from any tax laid by the state, or by any parish or body politic under the authority of the state, during the continuance of its charter.” It was held that a judgment holding this to be a valid exemption, and one which rendered void any attempt to tax its capital or real and personal property used in its business, or to tax its shareholders by imposing an obligation on the bank to pay a tax on its stock for them, did not estop the city and the taxing officers from taxing property held by the bank, but not as capital, or from taxing shares of stock in the hands of the shareholders, or from imposing a license tax. This result was reached, as the court points out, because the exemption clause might be entirely valid and inviolable as a contract, so as to exempt capital and business property, and yet, under many decisions of the court, might not prevent the taxation of the shares of stock, and upon the same principle might not prevent a tax or license upon its business. In the case at bar the situation is very different. The provision of the exemption clause in the Hewitt act is that “such bank and its shares of stock shall be exempt from all other taxation whatsoever, so long as said tax shall be paid during the corporate existence of such bank.” If this exemption clause is irrevocable, it certainly prevents any additional tax upon the property of the bank. That is clear. The former adjudication was that this exemption was irrevocable, and prevented the imposition of a tax even in the form of a license tax upon its business. If it prevents a license tax, a fortiori does it prevent a direct tax upon its property, tangible and intangible. The tax imposed by the revenue act of 1892 was called a “franchise tax,” but it has been held, both by the supreme court of the United States and of the court of appeals of Kentucky, to be in fact nothing but an ad valorem property tax. Henderson Bridge Co. v. Kentucky, 166 U. S. 150, 1.7 Sup. Ct. 532; Adams Exp. Co. v. Kentucky, 166 U. S. 171, 17 Sup. Ct. 527; Henderson Bridge Co. v. Com., 99 Ky. 623, 31 S. W. 486.
Nor can there be any doubt that the parties to the former adjudications and this litigation are the same. The real parties in interest in this cause among the defendants are Franklin county, the city of Frankfort, and the city of Louisville. It is for them that the board of valuation and assessment are about to apportion the estimated value of the franchise, and to certify it to them for the collection of taxes. The members of the board of valuation are *396nothing but their agents created under the law for the purpose of assessing this tax. If the parties in interest in whose favor the tax is to be assessed are bound bj the prior litigation, certainly the agencies acting for them under the law are equally bound. In this light the board of valuation and assessment is in respect to the former judgments privy to the city of Louisville and county of Franklin and the city of Frankfort. There' is no dispute that the county of Franklin and the city of Frankfort were parties to the respective suits pleaded as former adjudications. The only controversy which is made is whether the city of Louisville was a party to the prohibition suit set forth in the bill. The original litigation was in form a criminal prosecution against the bank for failure to pay a license. That prosecution was in the name of the city of Louisville. The subsequent litigation, however, was in the form of a proceeding in prohibition against the judge of the city court, in which the criminal prosecution had been conducted, on the ground that that court was exceeding its jurisdiction, because proceeding under a void law. To that writ of prohibition the city of Louisville was not formally made a party in the Jefferson circuit court, but the litigation before the Jefferson circuit court was conducted by the city of Louisville. It was the real party in interest. It was against it that the writ of prohibition was really directed, for at its instance and for its benefit the criminal prosecution had been begun. When, therefore, an appeal had been taken from the Jefferson circuit court to the court of appeals, the appellants -were the city of Louisville and the judge of the police court. By this means the city of Louisville formally made itself a party to the record, and the mandate which went down was as binding upon it as upon the judge of its court. Had it attempted to proceed with the prosecution, it might have been attached for. contempt. Bac. Abr. “Prohibition,” M. It is urged that the litigation was really a criminal litigation, and that a' judgment in a criminal case cannot be made the basis of a plea of res judicata in a civil action. The original case was criminal in form, but the subsequent litigation by writ of prohibition was civil, and the real parties to it were the defendant in the police court and the city of Louisville,- in whose interest the suit was prosecuted in that court. It would have been entirely proper to make the city of Louisville a party defendant to the original writ of prohibition. Indeed, some courts would hold that it was a necessary party. Armstrong v. County Court, 15 W. Va. 190; Walton v. Greenwood, 60 Me. 356. However this may be, the city of Louisville, admitting its interest, did appear as appellant, and so made itself a party to the whole litigation, and was so treated by the court of appeals of Kentucky. As the parties to this litigation are the same as those in the former suits except the board of assessment, which is in privity with the other defendants, and as the point adjudged is exactly the same, we can see no escape from the conclusion that the defendants here are estopped from asserting that the complainant has not a contact exempting it from any other taxation than *397that provided in the Hewitt law, and, therefore, that the act of November 11,1892, is an infringement of that contract, and impairs its obligation in violation of the constitution of the United States.
It is suggested that such a conclusion ousts this court from jurisdiction, because it makes the case turn on a question which does not arise under the laws or constitution of the United States. We cannot assent to this suggestion. The complainant asserts that it has a contract with the commonwealth in respect to taxation, the obligation of which the city of Louisville, the city, of Frankfort, and the county of Franklin, by the enforcement of a subsequent law of the state, are seeking to impair. The defendants deny the existence of such a contract, and we must determine whether, as between the parties, such a contract exists. It appears that, as between the complainant and the defendants, it has been conclusively adjudicated that such a contract exists. This relieves the court from re-examining that question as an original one between the present parties; but it does not free the court from the obligation to enforce the constitution of the United States, in favor of the complainant, by enjoining the enforcement of a law which will impair the obligation of a contract thus conclusively established. The ease of City of New Orleans v. Citizens’ Bank of Louisiana, 167 U. S. 371, 17 Sup. Ct. 527, which presented precisely this aspect, was begun in the circuit court of the United States, and was carried to the supreme court of the United States, and the jurisdiction by the circuit court was not even questioned.
It is argued that the federal courts, in considering the question whether a state law7 impairs the obligation of a contract, will not accept as conclusive the construction which thq,supreme court of the state has put upon its constitution or laws in determining the existence of a contract and its violation. This is true, and is settled by a long line of authorities. Shelby Co. v. Union & Planters’ Bank, 161 U. S. 149, 16 Sup. Ct. 558; Mobile & O. R. Co. v. Tennessee, 153 U. S. 492, 193. 14 Sup. Ct. 968; Bryan v. Board. 151 U. C. 659, 14 Sup. Ct. 465; Railroad Co. v. Palmes, 109 U. S. 256, 3 Sup. Ct. 193; Douglas v. Kentucky, 168 U. S. 488, 502, 18 Sup. Ct. 199, and cases cited. But the rule has application only where the judgment of the state court is under direct review, or in cases in which the opinion of the state court is cited merely as an authority and a precedent. It has no application to a case in which a prior judgment of the state court between the same parties is pleaded or is offered in evidence in a subsequent suit in a federal court as res judicata binding the parties. The state court is as much bound by the constitution of the United States as a federal court, and is vested with as complete jurisdiction in causes otherwise within its cognizance to decide, between the parties before it, whether a statute of the state impairs the obligation of a contract. Robb v. Connolly, 111 U. S. 624, 637, 4 Sup. Ct. 544. Such decision, embodied in a judgment unreversed, is as binding with respect to the point adjudged as if it had been rendered by the supreme court of the United States. The distinction between the right and duty of the supreme court to decide for itself the question of contract or *398no contract without regard to the state decisions, and its obligations to respect the bar of res judicata as between the parties, is quite clearly made in Douglas v. Kentucky, 168 U. S. 488, 503, 18 Sup. Ct. 199, although not expressly commented on. In that case, after maintaining in the strongest terms the obligation of the supreme court to exercise an independent judgment in determining the existence of a contract and its impairment, and after declining to follow a prior decision of the state court upon the subject, the court considered as a distinct matter the question whether the point had not been formerly adjudged in á state court between the same parties, and pointed out with much care that the point of the former adjudication was not the same as that then before the court. The whole discussion would have been wholly unnecessary if, as contended by counsel for defendants, the doctrine of res judicata has no application in the federal courts when the former adjudication is that of a state court upon a question arising under the federal constitution.
One other point remains for consideration. The answer pleads that a mandamus proceeding has been instituted in a state court by the city of Frankfort to compel the board of valuation and assessment to certify the apportioned valuation of the franchises of the complainant; that this mandamus proceeding was begun before the action under consideration, and is pending; and that the preliminary injunction issued by this court will be in effect an injunction against that proceeding in the state court. We do not think so. It is settled that the pendency of a suit in a state -court is no bar to a suit upon the same subject-matter in this court. City of North Muskegon v. Clark, 22 U. S. App. 522, 10 C. C. A. 591, and 62 Fed. 694, and cases therein cited. The injunction which we shall grant may be offered as a defense by the board of valuation and assessment in the court where the mandamus proceeding is pending, just as a judgment rendered in one of two pending suits for the same cause of action may be offered by supplemental pleading in the other. The sufficiency of the defense will be for that court. We do not enjoin any suit at all by our order; all we do enjoin is the certification of the taxes. That does not require the defendants to disobey an order of any other court, or restrain their prosecution of a suit therein. The demurrer to the bill must therefore be overruled, and the preliminary injunction prayed for must issue.