Argument for Appellees. determined. But if the jurisdiction depends upon a correct solution of the question, we submit that if the repealing act has the effect claimed for it by the demurrer and in argument here, it must be held to impair the contract rights of complainant. Planters' Bank v. Sharp, 6 How. 301; Edwards v. Kearzey, 96 U. S. 595; Curran v. Arkansas, 15 How. 304; Hawthorne v. Calef, 2 Wall. 10; Fisk v. Jefferson Parish, 116 U. S. 131; Mumma v. Potomac Co., 8 Pet. 281. A summary of the laws relating to the Metropolitan police board shows: 1. That all statutes on the subject were mandatory in their character and required the city of New Orleans and other municipalities composing the police district to pay the amount apportioned against them, and to levy and collect a sufficient tax to discharge that obligation. 2. That these statutes, up to 1874, made scrip issued by the board receivable for all taxes due to the municipalities, without any limitation, except that the municipalities should not be required to receive scrip for any one year in excess of the annual apportionment. 3. That act 33 of 1874 required taxes levied for these apportionments to be paid in cash; providing, however, that scrip issued prior to January 1, 1874, should be receivable for taxes due prior to that year, except for the interest, school, park taxes, etc., and in this respect depriving the scrip holders. of the right to use them in payment of all taxes, as permitted by prior laws. 4. Act No. 35 of 1877 repealed all these laws, relieving the municipalities of the duty and obligation of paying the apportionments, and withdrawing the power of levying taxes to pay them, and leaving the creditors of the police board without a debtor whom they could sue, and providing no remedy for the application of the assets of the board to the payment of its debts. 5. Three years later act No. 49 of 1880 was passed, pursuant to a constitutional ordinance of the State, which made the scrip receivable only for the taxes levied for the police fund in the years 1874, 1875, 1876. The defendant claims by demurrer, answer, and argument Argument for Appellees. that it was competent for the legislature to enact these laws, and that if they impaired the remedy of the scrip holders, said act 49 gave them a new and ample remedy. On the other hand, complainant asserts that the statute of 1877 was in contravention of the Constitution of the United States, and that act 49 of 1880, so far as it is claimed by defendant to be an adequate remedy in lieu of those previously taken away, is itself an impairment of his contract. As these contentions must be determined by a resort to the provisions of the Constitution of the United States, and are decisive of the rights of the parties, they clearly make a case arising under that Constitution, of which the Circuit Court had original jurisdiction. II. As to the third question, this involves a further consideration of the jurisdiction of the Circuit Court. Its jurisdiction of this case is assailed on the ground that the complainant, although an alien, is assignee of the claims he holds, the assignors thereof being citizens of Louisiana, of which State the defendants are also citizens. Also on the ground that some of the intervenors are citizens of Louisiana, and that complainant's suit is really for their benefit. The objection is founded upon the theory that the warrants and certificates held by complainant are choses in action, his title to which is derived through assignment by citizens of Louisiana; that he is suing to recover their contents, and that the exercise of jurisdiction is therefore prohibited by the act of March 3, 1887, which provides that the Circuit Court shall not "have cognizance of any suit except upon foreign bills of exchange to recover the contents of any promissory note or other chose in action in favor of any assignee unless such suit might have been prosecuted in such court to recover said contents if no assignment or transfer had been made." The contents of a contract, as a chose in action, are the rights created by it in favor of a party in whose behalf stipulations are made in it, which he has a right to enforce in a suit founded on the contract; and a suit to enforce such stipulations is a suit to recover such contents. Corbin v. County of Black Hawk, 105 U. S. 659. Opinion of the Court. Necessarily a suit to recover the contents must be brought against the party who made the stipulation, as in the case of a promissory note against the maker, or upon a bond against the obligor. In such case the assignee of the contract, note, or other chose in action, cannot sue in the Circuit Court, unless his assignor might have done so, because the suit is one to recover contents, and so within the exception of the statute. But this exception has never been extended to a case not clearly within it. Thus it has been held not to apply to a suit by an assignee of a chose in action to recover possession of the thing in specie, or damages for its wrongful caption or detention. Deshler v. Dodge, 16 How. 622; Ambler v. Eppinger, 137 U. S. 480; Bushnell v. Kennedy, 9 Wall. 387. The complainant's bill was brought not only in behalf of himself but of all other creditors similarly situated, not to recover contents, but to establish a fund out of which all should be paid pro rata. A suit to recover the contents of a chose in action is one to enforce the obligation thereof in toto. In this case complainant could have no decree for the deficiency, if the fund prove insufficient to pay him and all other creditors in full. The bill shows the necessity as well as propriety of proceeding as it does against the debtors of the board; the amounts owing by them constituting its sole assets, and the complainant being an alien, he was competent to sue in the Circuit Court. The case of Bean v. Smith, 2 Mason, 252, decided by Judge Story, establishes his right to sue in that court, notwithstanding he is a creditor by assignment. This case is quoted with approval in Ober v. Gallagher, 93 U. S. 206. MR. CHIEF JUSTICE FULLER, after stating the case, delivered the opinion of the court. The first and third questions propounded relate to the jurisdiction of the Circuit Court, which was invoked on two grounds: (1) that the case was one arising under the Opinion of the Court. Constitution of the United States; and (2) on diverse citizenship. 1. When a suit does not really and substantially involve a dispute or controversy as to the effect or construction of the Constitution, upon the determination of which the result depends, then it is not a suit arising under the Constitution. Shreveport v. Cole, 129 U. S. 36; Starin v. New York, 115 U. S. 248, 257; Gold Washing and Water Co. v. Keyes, 96 U. S. 199. The judicial power extends to all cases in law and equity arising under the Constitution, but these are cases actually and not potentially arising, and jurisdiction cannot be assumed on mere hypothesis. In this class of cases it is necessary to the exercise of original jurisdiction by the Circuit Court that the cause of action should depend upon the construction and application of the Constitution, and it is readily seen that cases in that predicament must be rare. Ordinarily the question of the repugnancy of a state statute to the impairment. clause of the Constitution is to be passed upon by the state courts in the first instance, the presumption being in all cases that they will do what the Constitution and laws of the United States require, Chicago & Alton Railroad Co. v. Wiggins Ferry Co., 108 U. S. 18; and if there be ground for complaint of their decision, the remedy is by writ of error under section 709 of the Revised Statutes. Congress gave its construction to that part of the Constitution by the twenty-fifth section of the Judiciary Act of 1789, and has adhered to it in subsequent legislation. But assuming that such repugnancy might be so set up as to form an independent ground of jurisdiction in the Circuit. Court, it becomes necessary, in order to dispose of the inquiry whether such a dispute or controversy was really involved here, to refer to certain legislation of the State of Louisiana. By act No. 74 of 1868, (Acts La. 1868, 85,) the parishes of Orleans, Jefferson, and St. Bernard were united into a district, called "the Metropolitan Police District of New Orleans, State of Louisiana," and a board created, styled the "Board of Metropolitan Police," upon which were conferred the Opinion of the Court. powers and duties pertaining to police government and discipline in that district, with power to issue warrants and certificates for the payment of the police and other expenses. These expenses were to be borne by the cities, towns, and parishes of the district, and apportionments or estimates thereof were to be made annually by the board against each of the cities and parishes, which were to be "binding upon the respective cities and towns interested therein," and the cities, towns, and parishes were empowered and directed to annually levy and collect taxes to raise the sums of money so estimated and apportioned, to be paid over to the state treasurer and constitute a fund to be paid out on warrants as provided. By act No. 44 of 1869, (Acts La. 1869, 42,) and act No. 92 of 1869, amending and reënacting the original act, (Acts La. 1869, 92,) warrants issued in payment of the salaries of officers, employés, and members of the Metropolitan police in accordance with act No. 74 of 1868 were made receivable for all parish and municipal licenses and taxes within the limits of the Metropolitan police district, provided the aggregate so received in each current year should not exceed the amount of the apportionment for that year. By act No. 41 of 1870, (Acts La. 1870, 74,) all warrants, checks, and orders issued in payment of the salaries of Metropolitan police, and all warrants, checks, and orders issued, or that might thereafter be issued, for the supplies and expenses of the board, were made receivable for all police and municipal taxes and debts to become due for the police of New Orleans, Jefferson, and Carrollton, provided that the aggregate of such warrants, checks, or orders so received in each current year should not exceed the apportionment. By act No. 33 of 1874, (Laws La. 1874, sec. 4, pp. 68, 70,) it was enacted, among other things, that all Metropolitan police taxes should be collected in cash, and that it should be unlawful to receive in payment for said taxes any warrants of indebtedness of any kind whatever, provided that warrants and certificates issued prior to January 1, 1874, should still be received for taxes due for the years prior to that date. In 1875, (Laws La. 1875, 35, No. 16,) an act was passed, to |