Adams, John (1735-1826) to Thomas B. Adams re: French convention and law of nations

Washington January 2. 1801
My dear Son

In one of your Letters you Say there is much murmuring concerning the Convention with France. This is natural. Those who have laboured to defeat the Negotiation and those who have endeavoured to make it unpopular, from the beginning will Still Strive to defeat and to disgrace the Result. I shall confine myself at present to one point the apparent Collision between this Convention and our Treaty with England. This is a Contradiction only in appearance. Nay when the Rule of Constitution is known, the appearance of Inconsistency vanishes. I wish you would look into Grotius and Puffendorf, among the Rules for the interpretation of Treaties, and send me extracts of the Law upon this point. I have no books here. [Vattell] I have found means to consult. In Book 2. Ch. 17th of that Jurist. In ss. 312. 313 314 you will find Rules which have relation to this subject, and among other Observations and reasonings these words "As to what relates to treaties, We are not obliged to accomplish, what a treaty prescribes any further than We have the Power; now We have not the Power of doing what another treaty forbids: in this case then, the Collision forms an exception to the treaty which prescribes, and that which forbids has the advantage; but all other things being equal, We are going to shew by an example, that a treaty cannot derogate from another more antient concluded with another State now hinder its effect, either directly or indirectly. [2] Ss 315. "4. The date of the laws or treaties furnishes new reasons for establishing the Exception, in the case where there is an opposition. If the opposition is found between two affirmative laws, or two affirmative treaties, concluded between the Same persons, or the Same States, the last date has the Advantage over the more ancient. For it is manifest, that these two Laws, or two treaties Springing from the Same power, the last may derogate from the first. But it is always to be supposed, that things are otherwise equal, if there be a collision between two treaties made with two different powers, the more ancient has the advantage. for no engagement can be entered into contrary to it, in the treaty afterwards made, and if this last be found, in any case, in compatible with the more ancient one, its execution is considered as impossible; because the person promising, had not the power of Acting contrary to his antecedent engagement."
This Authority is so full and direct, in print, that it ought to silence every doubt on that head [struck: in] [inserted: relative to] the present Convention. If my memory does not deceive me Grotius and Puffendorf are equally explicit. I wish upon to look into all the Writers on the Law of nations, for this point.
Your Affectionate Father
John Adams

T.B. Adams Esq

[docket]
The President of the U.S.
2 Jany 1801.
6th,,Do Recd,,
9th,,Do answd,,