The general principle usually stated is that there is no federal common law - that, in other words, the law which the federal courts apply consists wholly and exclusively of the federal Constitution, treaties, the statutes of Congress, and the laws common and statutory of the several States of the Union.

The common law of the States consists of the principles of the English common law, developed and modified by American custom and judicial precedent. Having this great common substratum of the English common-law principles, the non-statutory law of the several States is, in very many respects, the same throughout the United States. But in other respects, statutory enactment and divergent customs and judicial determinations have led to important differences.

In general, however, excepting where statutes have expressly amended the English common law as it was at the time of the separation from England, or where clear judicial dicta to the contrary are to be found, the general doctrines of the English common law are held to be in force.32 decision by the state court on the particular question involved, then the federal courts properly claim the right to give effect to their own judgment as to what is the law of the State applicable to the case, even where a different view has been expressed by the state court after the rights of the parties accrued. But even in such cases, for the sake of comity and to avoid confusion, the federal court should always lean to an agreement with the state court if the question is balanced with doubt."

Justices Holmes, White, and McKenna dissented.

31 Chapter XLVIII (The Obligation Of Contracts. 488. The Obligation Of Contracts Clause).

32 Louisiana, whose law is founded on the Roman civil law, is an exception to this, but statute and judicial practice have brought the Louisiana law a long way toward conformity to the common law.

Strictly applying the doctrine that the federal courts, when exercising jurisdiction derived from the character of the parties to the causes tried, will apply the laws of the States applicable thereto, there is left no room for a federal common law, for, when not applying state law, the federal courts have only the function of interpreting and applying the federal Constitution and the treaties entered into and the laws passed in pursuance thereof.

That the federal courts have no jurisdiction derived directly from the common law has been unquestioned since the early case of Ex parte Bollman,33 in which the court say:

"As preliminary to any investigation of the merits of this motion, this court deems it proper to declare that it disclaims all jurisdiction not given by the Constitution or by the laws of the United States. Courts which originate in the common law possess a jurisdiction which must be regulated by the common law until some statute shall change their established principles; but courts which are created by written law, and whose jurisdiction is defined by written law, cannot transcend that jurisdiction. It is unnecessary to state the reasoning on which this opinion is founded, because it has been repeatedly given by this court; and with the decisions heretofore rendered on this point, no member of the bench has, even for an instant, been dissatisfied. The reasoning from the bar, in relation to it, may be answered by the single observation, that for the meaning of the term habeas corpus, resort must unquestionably be had to the common law; but the power to award the writ by any of the courts of the United States, must be given by the written law."

That the federal courts not only have no common-law jurisdiction, but that, generally speaking, there is no federal common law as distinguishable from statute law (Constitution, treaties, acts of Congress) was declared in the comparatively early case of Wheaton v. Peters.34 In that case the court say:

"It is clear that there can be no common law of the United States. The Federal Government is composed of twenty-four sovereign and independent States, each of which may have its local usages, customs and common law. There is no principle which pervades the Union and has the authority of law that is not embodied in the Constitution or laws of the Union. The common law could be made a part of Our federal system only by legislative action." 35

33 4 Cr. 75; 2 L. ed. 554.

34 8 Pet. 591; 8 L. ed. 1055.