The administrative authority's power 'to regulate commerce among the several States' means commerce that affected more than one State. It's talking about the legal entity of the State, not everything that crosses State lines.
Gibbons v. Ogden
The subject to which the power is next applied, is to commerce "among the several States." The word "among" means intermingled with. A thing which is among others, is intermingled with them. Commerce among the States, cannot stop at the external boundary line of each State, but may be introduced into the interior.
It is not intended to say that these words comprehend that commerce, which is completely internal, which is carried on between man and man in a State, or between different parts of the same State, and which does not extend to or affect other States. Such a power would be inconvenient, and is certainly unnecessary.
Comprehensive as the word "among" is, it may very properly be restricted to that commerce which concerns more States than one. The phrase is not one which would probably have been selected to indicate the completely interior traffic of a State, because it is not an apt phrase for that purpose; and the enumeration of the particular classes of commerce, to which the power was to be extended, would not have been made, had the intention been to extend the power to every description. The enumeration presupposes something not enumerated; and that something, if we regard the language or the subject of the sentence, must be the exclusively internal commerce of a State. The genius and character of the whole government seem to be, that its action is to be applied to all the external concerns of the nation, and to those internal concerns which affect the States generally; but not to those which are completely within a particular State, which do not affect other States, and with which it is not necessary to interfere, for the purpose of executing some of the general powers of the government. The completely internal commerce of a State, then, may be considered as reserved for the State itself.
------------
Joseph Story, Commentaries on the Constitution
§ 1075 The constitution is one of limited and enumerated powers; and none of them can be rightfully exercised beyond the scope of the objects, specified in those powers. It is not disputed, that, when the power is given, all the appropriate means to carry it into effect are included. Neither is it disputed, that the laying of duties is, or may be an appropriate means of regulating commerce. But the question is a very different one, whether, under pretence of an exercise of the power to regulate commerce, congress may in fact impose duties for objects wholly distinct from commerce. The question comes to this, whether a power, exclusively for the regulation of commerce, is a power for the regulation of manufactures? The statement of such a question would seem to involve its own answer. Can a power, granted for one purpose, be transferred to another? If it can, where is the limitation in the constitution? Are not commerce and manufactures as distinct, as commerce and agriculture? If they are, how can a power to regulate one arise from a power to regulate the other? It is true, that commerce and manufactures are, or may be, intimately connected with each other. A regulation of one may injuriously or beneficially affect the other. But that is not the point in controversy. It is, whether congress has a right to regulate that, which is not committed to it, under a power, which is committed to it, simply because there is, or may be an intimate connexion between the powers. If this were admitted, the enumeration of the powers of congress would be wholly unnecessary and nugatory. Agriculture, colonies, capital, machinery, the wages of labour, the profits of stock, the rents of land, the punctual performance of contracts, and the diffusion of knowledge would all be within the scope of the power; for all of them bear an intimate relation to commerce. The result would be, that the powers of congress would embrace the widest extent of legislative functions, to the utter demolition of all constitutional boundaries between the state and national governments. When duties are laid, not for purposes of revenue, but of retaliation and restriction, to countervail foreign restrictions, they are strictly within the scope of the power, as a regulation of commerce. But when laid to encourage manufactures, they have nothing to do with it. The power to regulate manufactures is no more confided to congress, than the power to interfere with the systems of education, the poor laws, or the road laws of the states. It is notorious, that, in the convention, an attempt was made to introduce into the constitution a power to encourage manufactures; but it was withheld. Instead of granting the power to congress, permission was given to the states to impose duties, with the consent of that body, to encourage their own manufactures; and thus, in the true spirit of justice, imposing the burthen on those, who were to be benefited.
-----
It seems that the public is being drilled into believing the feds are the "real government," and that state government is something less.
Agreed. And that misconception is killing us. :-(
Document 19
James Madison to Joseph C. Cabell
13 Feb. 1829Letters
4:14--15
For a like reason, I made no reference to the "power to regulate commerce among the several States." I always foresaw that difficulties might be started in relation to that power which could not be fully explained without recurring to views of it, which, however just, might give birth to specious though unsound objections. Being in the same terms with the power over foreign commerce, the same extent, if taken literally, would belong to it. Yet it is very certain that it grew out of the abuse of the power by the importing States in taxing the non-importing, and was intended as a negative and preventive provision against injustice among the States themselves, rather than as a power to be used for the positive purposes of the General Government, in which alone, however, the remedial power could be lodged.
How far afield we have strayed, on nothing more than specious sophistry.