119. A federal court sitting within a State is a court of that State within the meaning of the Constitution and laws of the Union, “and as such, has an equal right with the State courts to fix the construction of the local law.”[300] A State tribunal’s decision must conform to that of the Supreme Court of the United States, but a federal court sitting within a State follows the highest State tribunal unless the decision of that tribunal has been set aside by the Supreme Court. Such procedure “tends to preserve harmony in the exercise of the judicial power, in the State and federal tribunals.” This means that the statute law of a State,—and a fixed and received construction by a State in its own courts, makes a part of the statute law,—is accepted by the federal courts sitting in the State. But the federal court there is not bound to follow such State precedents and authorities; the court possesses a jurisdiction independent of that conferred by State authority.[301] Thus it may be stated as accepted American constitutional law that where there are two co-ordinate jurisdictions, and especially “with regard to the law of real estate and the construction of State constitutions and statutes” and where are concerned “the doctrines of commercial law and general jurisprudence” the federal courts sitting in a State exercise their own judgment, “but even in such cases, for the sake of harmony and to avoid confusion, the federal courts will lean towards an agreement of views with the State courts, if the question seems to them balanced with doubt.”[302] To the extent that a federal court sitting within a State follows State laws and decisions, to that extent is there a common law of the United States. There is, however, no national common or customary law of the United States; its law is statutory. But the interpretation of the Constitution by the judicial power of the United States is necessarily influenced by the fact that its provisions are framed in the language of the English common law, and are to be read in the light of its history. The code of constitutional and statutory construction which, therefore, is gradually formed by the judgments of (the Supreme) Court, in the application of the Constitution and the laws and treaties made in pursuance thereof, has for its basis so much of the common law as may be implied in the subject, and constitutes a common law resting on national authority.[303] NOTE: For an account of acts of Congress declared unconstitutional by the Supreme Court see _The Supreme Court and Unconstitutional Legislation_, B. F. Moore, Columbia University Studies, vol. liv., No. 2, 1913. CHAPTER IX THE LAW OF STATE COMITY, TERRITORIES AND POSSESSIONS