Foster & Elam v. Neilson (1829) 27 U.S. 253, was an action to recover certain lands in Louisiana, the controlling question was as to whom the country between the Iberville and the Perdido rightfully belonged at the time the title of the plaintiff in that case was acquired. The United States, the court said, had perseveringly insisted that by the treaty of St. Ildefonso made October 1, 1800, Spain ceded the disputed territory as part of Louisiana to France, and that France by the treaty of Paris of 1803 ceded it to the United States. Spain insisted that the cession to France comprehended only the territory which at that time was denominated Louisiana. After examining various articles of the treaty of St. Ildefonso, Chief Justice Marshall, speaking for the court, said: "In a controversy between two nations concerning national boundary, it is scarcely possible that the courts of either should refuse to abide by the measures adopted by its own government. There being no common tribunal to decide between them, each determines for itself on its own rights, and if they cannot adjust their differences peaceably, the right remains with the strongest. The judiciary is not that department of the government to which the assertion of its interests against foreign powers is confided; and its duty commonly is to decide upon individual rights, according to those principles which the political departments of the nation have established. If the course of the nation has been a plain one, its courts would hesitate to pronounce it erroneous." Again: "After these acts of sovereign power over the territory in dispute, asserting the American construction of the treaty by which the government claims it, to maintain the opposite construction in its own courts would certainly be an anomaly in the history and practice of nations. If those departments which are entrusted with the foreign intercourse of the nation, which assert and maintain its interests against foreign powers, have unequivocally asserted its rights of dominion over a country of which it is in possession, and which it claims under a treaty; if the legislature has acted on the construction thus asserted, it is not in its own courts that this construction is to be denied. A question like this respecting the boundaries of nations, is, as has been truly said, more a political than a legal question; and, in its discussion, the courts of every country must respect the pronounced will of the legislature." The Supreme Court suggested that some treaties might address themselves to the political, not the judicial department inasmuch as in some cases the legislature must execute the contract before it can become a rule for the Court. The Supreme Court did not say that such a treaty did not create any obligations whatsoever, nor did it suggest that the judicial department might be prohibited from noting when the political department has not yet done what it (ostensibly) contracted to do. The Court stated that:"If a Spanish grantee had obtained possession of the land in dispute, so as to be the defendant, would a court of the United States maintain his title under a Spanish grant made subsequent to the acquisition of Louisiana, singly on the principle that the Spanish construction of the treaty of St. Ildefonso was right, and the American construction wrong? Such a decision would subvert those principles which govern the relations between the legislative and judicial departments, and mark the limits of each." Chief Justice Marshall has said, "That a treaty is to be regarded, in courts of justice, as equivalent to an act of the legislature, whenever it operates of itself, without the aid of any legislative provision." Chief Justice Marshall also said: "A treaty is, in its nature, a contract between two nations, not a legislative act. It does not generally effect, of itself, the object to be accomplished; especially, so far as its operation is infraterritorial; but is carried into execution by the sovereign power of the respective parties to the instrument. In the United States, a different principle is established. Our Constitution declares a treaty to be the law of the land. It is consequently to be regarded in courts of justice as equivalent to an act of the Legislature, whenever it operates of itself, without the aid of any legislative provision. But when the terms of the stipulation import a contract - when either of the parties engages to perform a particular act, the treaty addresses itself to the political, not the judicial department; and the Legislature must execute the contract, before it can become a rule for the court."