Early 1760s. The book was much discussed in the "Whipping post club" among Bostonians such as John and Samuel Adams, James Otis, etc. in the 1760s. James Otis specifically refers to it in his "The Rights of the British Colonies Asserted and Proved".
The evidence indicates the entire *IDEA* of becoming a Republic of States United into a confederation was put forth in Vattel's book.
Vattel literally put the idea into the heads of the Founders.
"Finally, several sovereign and independent states may unite themselves together by a perpetual confederacy, without ceasing to be, each individually, a perfect state. They will together constitute a federal republic: their joint deliberations will not impair the sovereignty of each member, though they may, in certain respects, put some restraint on the exercise of it, in virtue of voluntary engagements. A person does not cease to be free and independent, when he is obliged to fulfil engagements which he has voluntarily contracted."
Very interesting, thanks.
Stonecutters hate de Vattel and any talk of Natural Law.