What would be the effect of the United States ratifying a treaty that is incompatible with its constitution?

  • 3
    Some more detail would be good. Some treaties might be clearly unconstitutional (e.g. requiring the government to violate constitutional rights without cause or due process), some might have subtler effects that would not be immediately obvious. Especially in the latter case, there might need to be a court decision to establish it was unconstitutional, although that would require someone to have standing to bring a court case, and it all disappears into legal thickets. So it's possible a treaty could be passed without knowing if it violates the constitution.
    – Stuart F
    Dec 5, 2022 at 16:23

1 Answer 1


Does a treaty have to be compatible with the US constitution to be implemented?


A treaty that is incompatible with the U.S. Constitution is void to the extent it is unconstitutional. See, e.g., Doe v. Braden, 57 U.S. (16 How.) 635, 657 (1853) ("The treaty is . . . a law made by the proper authority, and the courts of justice have no right to annul or disregard any of its provisions, unless they violate the Constitution of the United States."); The Cherokee Tobacco, 78 U.S. (11 Wall.) 616, 620 (1870) ("It need hardly be said that a treaty cannot change the Constitution or be held valid if it be in violation of that instrument."); De Geofroy v. Riggs, 133 U.S. 258, 267 (1890) ("It would not be contended that [the treaty power] extends so far as to authorize what the constitution forbids."); Asakura v. City of Seattle, 265 U.S. 332, 341 (1924) ("The treaty-making power of the United States . . . does not extend ‘so far as to authorize what the Constitution forbids.’") (quoting De Geofroy, 133 U.S. at 267); Reid v. Covert, 354 U.S. 1, 16 (1957) ("This Court has regularly and uniformly recognized the supremacy of the Constitution over a treaty.").

  • By chance, do you know of any treaties that are still in effect today despite being incompatible with the US constitution, due to necessity?
    – AlanSTACK
    Dec 5, 2022 at 16:27
  • 3
    @AlanSTACK No. There are no such treaties. There may be treaties that are incompatible with the U.S. Constitution that have not been declared unconstitutional because the manner in which they are unconstitutional involves a hypothetical possibility hasn't presented itself in real life situations, or because the legal process has not yet run its course, but there are no treaties that are in effect despite being incompatible with the U.S. Constitution due to "necessity." That is not a defense against unconstitutionality.
    – ohwilleke
    Dec 5, 2022 at 16:29
  • 1
    @ohwilleke: What rules would apply to a treaty which was legitimate when it was ratified if the Constitution were amended in such a fashion as to be incompatible with it? Suppose, for example, that prior to the Civil War US had ratified a treaty allowing a foreign country to use US ports to transfer slaves between ships?
    – supercat
    Dec 5, 2022 at 23:29
  • 4
    @supercat The constitution has absolute precedence over every other form of law. If an amendment contradicted a treaty, then the incompatible portion of that treaty would have to be discarded or ignored as soon as the amendment took effect. Whether that invalidates the entire treaty or just a small part of it will depend on the details of that specific treaty.
    – bta
    Dec 5, 2022 at 23:47
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    @Clockwork-Muse the US modified its statutory law to implement the provisions of the Berne convention. There's no "pushing through": the executive signed the convention, the senate ratified it, congress passed a bill changing copyright law, and the president signed it. The legislative and executive branches could have made these changes without signing the treaty. Acceding to the treaty increases protection for the works of US authors outside the US, though, which is no doubt why they did it.
    – phoog
    Dec 6, 2022 at 10:07

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