"So it is clear that the framers of the Constitution intended, not merely that exports should not be made a source of revenue to the national government, but that the national government should put nothing in the way of burden upon such exports. If all exports must be free from national tax or duty, such freedom requires, not simply an omission of a tax upon the articles …

That is to say, "what cannot be done directly because of constitutional restriction cannot be accomplished indirectly by legislation which accomplished the same result.*** Or, in other words, constitutional provisions, whether operating by way of grant or limitation, are to be enforced according to their letter and spirit, and cannot be evaded by any legislation which, though …

Thus a federal stamp tax on a foreign bill of lading is a tax on exports, since, it is the equivalent of a direct tax on the articles included in the bill of lading.

This court has repeatedly laid down the principle that a contemporaneous legislative exposition of the Constitution, when the founders of our government and framers of our Constitution were actively participating in public affairs, acquiesced in for a long term of years, fixes the construction to be given its provisions.

For these reasons, we must conclude that, under the established rule of construction, the tax as laid in the present case was within the constitutional prohibition.

Similarly, with respect to federal taxation of articles exported from any State, the constitutional inhibition gives immunity to the process of exportation and to the transactions and documents embraced in that process.

`We are not here confronted with a question of the extent of the powers of Congress, but one of the limitations imposed by the Constitution on its action, and it seems to us clear that the same rule and spirit of construction must also be recognized.

But the present tax is not on the articles of import and export; nor is it the equivalent of a direct tax on the articles, as was held to be true of stamp taxes on foreign bills of lading

In the former they are subject to the regulation of Congress; in the latter to that of the State, and to enforce the proper relation between Congress and the State the full control of each over the commerce subject to its dominion must be preserved.

—to carry them into full execution; in other words, if the Constitution in its grant of powers is to be so construed that Congress shall be able to carry into full effect the powers granted, it is equally imperative that where prohibition or limitation is placed upon the power of Congress that prohibition or limitation should be enforced in its spirit and to its entirety. It would be a …

[CITATION] Department of Revenue v. Association of Wash. Stevedoring Cos.