When once the general theory is comprehended, numerous difficulties remain to be solved in its application; for the sovereignty of the Union is so involved in that of the states, that it is impossible to distinguish its boundaries at the first glance. The whole structure of the government is artificial and conventional; and it would be ill-adapted to a people which has not long been accustomed to conduct its own affairs, or to one in which the science of politics has not descended to the humblest classes of society. I have never been more struck by the good sense and the practical judgment of the Americans than in the ingenious devices by which they elude the numberless difficulties resulting from their federal constitution. I scarcely ever met with a plain American citizen who could not distinguish, with surprising facility, the obligations created by the laws of congress from those created by the laws of his own state; and who, after having discriminated between the matters which come under the cognizance of the Union, and those which the local legislature is competent to regulate, could not point out the exact limit of the several jurisdictions of the federal courts and the tribunals of the state. The constitution of the United States is like those exquisite productions of human industry which ensure wealth and renown to their inventors, but which are profitless in any other hands. This truth is exemplified by the condition of Mexico at the present time. The Mexicans were desirous of establishing a federal system, and they took the federal constitution of their neighbors the Anglo-Americans as their model, and copied it with considerable accuracy.[157] But although they had borrowed the letter of the law, they were unable to create or to introduce the spirit and the sense which gave it life. They were involved in ceaseless embarrassments between the mechanism of their double government; the sovereignty of the states and that of the Union perpetually exceeded their respective privileges, and entered into collision; and to the present day Mexico is alternately the victim of anarchy and the slave of military despotism.