In this extract from his popular essays Letters from a Farmer, published in 1768, John Dickinson comments on the constitutionality of the Townshend duties:

“There is another late act of parliament, which appears to me to be unconstitutional, and as destructive to the liberty of these colonies, as that mentioned in my last letter – that is the act for granting the duties on paper, glass, etc. [the Townshend Act].

The parliament unquestionably possesses a legal authority to regulate the trade of Great Britain and all her colonies. Such an authority is essential to the relation between a mother country and her colonies; and necessary for the common good of all. He, who considers these provinces as states distinct from the British empire, has very slender notions of justice, or of their interests. We are but parts of a whole; and therefore there must exist a power somewhere to preside, and preserve the connection in due order. This power is lodged in the parliament; and we are as much dependent on Great-Britain, as a perfectly free people can be on another.

These colonies require many things for their use, which the laws of Great Britain prohibit them from getting anywhere but from her. Such as paper and glass. That we may be legally bound to pay any general duties on these commodities relative to the regulation of trade is granted. But we being obliged by the laws to take from Great-Britain, any special duties imposed on their exportation to us only, with intention to raise a revenue from us only, are as much taxes, upon us, as those imposed by the Stamp Act.

Some persons perhaps may say, that this act lays us under no necessity to pay the duties imposed, because we may ourselves manufacture the articles on which they are laid; this continent is a country of planters, farmers, and fishermen; not of manufacturers. The difficulty of establishing particular manufactures in such a country is almost insuperable. Great-Britain has prohibited the manufacturing iron and steel in these colonies, without any objection being made to her right of doing it. This authority, she will say, is founded on the original intention of settling these colonies; that is, that we should manufacture for them, and that they should supply her with materials.

Here then, my dear country men ROUSE yourselves, and behold the ruin hanging over your heads. If you ONCE admit, that Great-Britain may lay duties upon her exportations to us, for the purpose of levying money from us only, she then will have nothing to do, but to lay those duties on the articles which she prohibits us to manufacture – and the tragedy of American liberty is finished.”