How have U.S. Supreme Court opinions cited founding-era treaties or non-constitutional texts when interpreting the First Amendment?

Checked on January 27, 2026
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Executive summary

The Supreme Court has sometimes invoked Founding‑era materials — including treaties, founding-era writings, and early practice — when construing the First Amendment, but it does so selectively and within tight methodological limits: treaties are treated as potentially binding domestic law only where text and context so provide, while historical or non‑constitutional texts inform rather than control modern First Amendment doctrines [1] [2] [3].

1. The Court’s basic posture toward founding‑era materials

The Court frequently reviews history and founding‑era understandings when approaching certain First Amendment questions, particularly the Establishment Clause, but it has not adopted an across‑the‑board rule that Founding‑era sources dictate outcomes; instead the Court treats history as one interpretive tool among others and often reserves judgment about how far original practice should constrain modern government action [4] [3] [5].

2. Treaties as a special category: textual limits and Boos v. Berry

When a treaty intersects with speech rights, the Court stresses that treaties do not automatically override constitutional guarantees and will be read in light of constitutional limits; in Boos v. Berry the Court held that a treaty‑based obligation to protect foreign embassies could not justify legislation that violated the First Amendment, illustrating the rule that treaty obligations cannot be read to erode core constitutional freedoms unless the treaty’s text and structure clearly require that result [6] [2].

3. How the Court uses treaty‑interpretation techniques without displacing constitutional analysis

The Court applies ordinary principles of treaty interpretation — looking to text, drafting history, and authentic language versions — when the question is what a treaty requires, but it stops short of allowing treaty meaning to trump constitutional rights; the Constitution’s Supremacy Clause makes treaties federal law, yet the Court treats the Constitution itself as the higher constraint when speech and religion claims collide with international commitments [1] [7] [2].

4. Founding‑era non‑constitutional texts and the Establishment Clause doctrine

In Establishment Clause cases the Court has sometimes pointed to founding‑era metaphors and practices — Jefferson’s “wall of separation” and contemporaneous practices regarding coercion and religious exercise are often cited — but the Justices have also been explicit that historical reference is not dispositive and that many modern disputes require balancing current pluralist values with historical understanding, as seen in cases like Lynch and American Legion where history informed but did not fully determine the outcome [8] [4] [3].

5. The methodological debate: original meaning, the Second Founding, and selective use of history

Scholars and some Justices argue for stronger weight to Founding‑era materials (originalism), while others push for a living or pragmatic approach; recent academic calls to consider the “Second Founding” (post‑Civil War Reconstruction) show that which historical moment one privileges changes doctrinal implications for the First Amendment, and the Court’s own practice reflects this debate by citing different historical periods selectively and sometimes acknowledging that historical evidence can be ambiguous or incomplete [5] [9] [10].

6. The practical pattern: context, text, and restraint

The practical pattern in Court opinions is clear: treaties will be parsed like other federal instruments but will not be read to authorize First Amendment intrusions except under compelling textual evidence, and non‑constitutional founding texts serve as persuasive background that can illuminate but not mechanically control modern First Amendment adjudication; the Justices therefore use history to legitimate outcomes or limit doctrines, but they also make judgment calls when history is silent or contested [6] [1] [3].

Want to dive deeper?
How did Boos v. Berry shape later First Amendment cases involving international obligations?
Which Supreme Court opinions have most heavily relied on Founding‑era practice to resolve Establishment Clause disputes?
What arguments do proponents of the 'Second Founding' make for its relevance to modern First Amendment interpretation?