Mr. Chief Justice Waite
delivered the opinion of the court.
After stating the facts in the language cited above, he continued :
In our opinion this is not a suit arising under the Constitution or laws of the United States, within the meaning of - that .term as used in the removal act. If the courts of Missouri gave a wrong construction to the laws of Illinois in the' judgment set up as an estoppel,' that error cannot be corrected by means of a transfer of this suit'from the State court to the Circuit Court-of the United States. So long as. the judgment stands, it cannot, be impeached collaterally in the courts of the United States any more than in .those of the State, by showing that-if due effect had been given to the laws it would have been the other way. If it has the effect of an estoppel, as is claimed, it' will continue to have that effect until reversed or set aside in some appropriate form of proceeding instituted directly for that purpose;.. The courts of the United States must, give it the same effect as a judgment that it has in the courts-of the State. . Whether as a judgment it operates as an estoppel does not depend on the Constitution or laws of. the United States.-' The. correct decision of this .-question of estoppel, therefore, does not depend on the construction of the Constitution or laws of' the-United States, but on the effect of a .judgment under- .the-' laws of Missouri. The public act's of Illinois are in no way involved. If full faith and credit were not given to them by. the Missouri- court, in the judgment which has been rendered; that may entitle the railroad company.to a review of the. judgment here on a writ of error, but in no. other way • can this jor any other court of the United-States invalidate, that -judgment on .account .'of such mistakes, if any were in fact made.
Another ground-taken in support of the jurisdiction of the' circuit court upon the removal is, if wé understand the argument of the counsel for the plaintiff in error, that the laws of Illinois, rightly construed, prohibit such a contract as it is alleged has been made, and as the Missouri court decided the other way when the former judgment was rendered, a transfer may be made so as to' avoid" a like error in this suit. The question thus presented is not what' faith and credit must bé given- the public acts of Illinois in Missouri, but what the public acts of Illinois, when rightly interpreted, mean. That does not depend on the Constitution or laws of the United .States, but on the Constitution and laws of the State alone. '
' It is not even alleged in the petition for removal, or claimed in argument, that the courts of Illinois have as yet actually given the statutes in question any such construction as it is contended they should have.' The most that can be insisted upon from all the allegations is, that on account of what "has been done in other cases, the railroad company expects, when an opportunity occurs, the courts of Illinois will decide that the laws of that State gave the company no power to bind itself in the way the Missouri court has determined it did. So that the position of the railroad company on this application seems to be, that, while the questions arising on the effect of the -public acts are apparently open in the courts of Illinois, and nothing has been.done which, even on, the. principles of comity, can bind the courts of Missouri, a suit pending in a Missouri court may be removed to a court of the United States, because the Missouri courtj on a former occasion, éonstrued a public law of Illinois, which is involved, differently from what it should have done. To allow a removal upon such grounds would-be to say that a suit arises under'the Constitution and laws of the United States whenever the public acts of one State are to be construed in an action pending in a court of another State. Clearly this is not so. Even if it be true, as is contended by the counsel for the plaintiff in error, that a suit can be removed as soon as a federal question becomes involved, it is sufficient to say that in this case such a' question has not arisen. Until the Missouri court fails, in this suit, to give full faith and credit to the .public acts of Illinois, no case has arisen to which the jurisdic tion of the courts of the United States can attach, and then only for the correction of the errors that have been committed. .It is not.enough that in other cases decisions have been made which, if followed in .this, will be erroneous. Until the error has actually been committed in this case, a federal question has not become involved. The presumption in all cases is that the courts of the States will do what the Constitution and laws of the United States require, and. removals cannot be effected to the courts of the United States because of fear that they will not.
The order remanding the ecmse is affirmed.