Under the more perfect mode of federation, where every citizen of each particular State owes obedience to two Governments, that of his own state and that of the federation, it is evidently necessary not only that the constitutional limits of the authority of each should be precisely and clearly defined, but that the power to decide between them in any case of dispute should not reside in either of the Governments, or in any functionary subject to it, but in an umpire independent of both. There must be a Supreme Court of justice, and a system of subordinate Courts in every State of the Union, before whom such questions shall be carried, and whose judgment on them, in the last stage of appeal, shall be final. Every State of the Union, and the Federal Government itself, as well as every functionary of each, must be liable to be sued in those Courts for exceeding their powers, or for non-performance of their federal duties, and must in general be obliged to employ those Courts as the instrument for enforcing their federal rights. This involves the remarkable consequence, actually realised in the United States, that a Court of justice, the highest federal tribunal, is supreme over the various Governments, both State and Federal; having the right to declare that any law made, or act done by them, exceeds the powers assigned to them by the Federal Constitution, and, in consequence, has no legal validity. It was natural to feel strong doubts, before trial had been made, how such a provision would work; whether the tribunal would have the courage to exercise its constitutional power; if it did, whether it would exercise it wisely and whether the Governments would consent to submit peaceably to its decision. The discussions on the American Constitution, before its final adoption, give evidence that these natural apprehensions were strongly felt; but they are now entirely quieted, since, during the two generations and more which have subsequently elapsed, nothing has occurred to verify them, though there have at times been disputes of considerable acrimony, and which became the badges of parties, respecting the limits of the authority of the Federal and State Governments.
The eminently beneficial working of so singular a provision is probably, as M. de Tocqueville remarks, in a great measure attributable to the peculiarity inherent in a Court of justice acting as such- namely, that it does not declare the law eo nomine and in the abstract, but waits until a case between man and man is brought before it judicially involving the point in dispute: from which arises the happy effect that its declarations are not made in a very early stage of the controversy; that much popular discussion usually precedes them; that the Court decides after hearing the point fully argued on both sides by lawyers of reputation; decides only as much of the question at a time as is required by the case before it, and its decision, instead of being volunteered for political purposes, is drawn from it by the duty which it cannot refuse to fulfil, of dispensing justice impartially between adverse litigants. Even these grounds of confidence would not have sufficed to produce the respectful submission with which all authorities have yielded to the decisions of the Supreme Court on the interpretation of the Constitution, were it not that complete reliance has been felt, not only on the intellectual pre-eminence of the judges composing that exalted tribunal, but on their entire superiority over either private or sectional partialities. This reliance has been in the main justified; but there is nothing which more vitally imports the American people than to guard with the most watchful solicitude against everything which has the remotest tendency to produce deterioration in the quality of this great national institution. The confidence on which depends the stability of federal institutions was for the first time impaired by the judgment declaring slavery to be of common right, and consequently lawful in the Territories while not yet constituted as States, even against the will of a majority of their inhabitants. This memorable decision has probably done more than anything else to bring the sectional division to the crisis which has issued in civil war. The main pillar of the American Constitution is scarcely strong enough to bear many more such shocks.
The tribunals which act as umpires between the Federal and the State Governments naturally also decide all disputes between two States, or between a citizen of one State and the government of another. The usual remedies between nations, war and diplomacy, being precluded by the federal union, it is necessary that a judicial remedy should supply their place. The Supreme Court of the Federation dispenses international law, and is the first great example of what is now one of the most prominent wants of civilised society, a real International Tribunal.
The powers of a Federal Government naturally extend not only to peace and war, and all questions which arise between the country and foreign governments, but to making any other arrangements which are, in the opinion of the States, necessary to their enjoyment of the full benefits of union. For example, it is a great advantage to them that their mutual commerce should be free, without the impediment of frontier duties and custom-houses. But this internal freedom cannot exist if each State has the power of fixing the duties on interchange of commodities between itself and foreign countries; since every foreign product let in by one State would be let into all the rest. And hence all custom duties and trade regulations, in the United States, are made or repealed by the Federal Government exclusively.
