What legal challenges succeeded against state 'anti‑Sharia' or foreign‑law bans, and on what grounds?

1. The lead victory: Oklahoma’s amendment overturned and why

The most prominent successful legal challenge targeted Oklahoma’s 2010 constitutional amendment (SQ 755), which voters approved but that the ACLU and CAIR challenged on behalf of Muneer Awad; a federal appeals court unanimously upheld a lower court ruling blocking the amendment because it effectively condemned one faith and the state could not point to any actual problem the amendment solved — the courts found the amendment singled out “Sharia” and treated a religious system as suspect in violation of the First Amendment ^{[1] [2]}.

2. Legal grounds that carried the day: Free Exercise, Establishment, equal treatment and vagueness

The successful challenges relied on classic constitutional doctrines: the Free Exercise and Establishment Clauses and Equal Protection principles, with courts emphasizing that laws singling out a religion are constitutionally suspect, that plaintiffs showed no real-world instances where Sharia had improperly intruded into state courts, and that the bans were often vague or overbroad in ways that would interfere with courts’ ordinary function — all legal reasoning documented by civil‑liberties groups and court rulings brought against Oklahoma’s amendment ^{[1] [2] [3] [4]}.

3. Broader legal critiques: interference with judicial function and international law

Beyond religious‑freedom claims, lawyers and professional bodies warned that blanket bans on “foreign” or “religious” law would impair judges’ ability to resolve ordinary interstate and international disputes — affecting enforcement of contracts, family law decisions involving foreign marriages or adoptions, and international comity — a practical harm highlighted by the ABA and legal commentators opposing such bans ^{[5] [3] [4]}.

4. The political and advocacy context that shaped litigation

The anti‑Sharia laws largely followed model text circulated by groups such as American Laws for American Courts (ALAC), and opponents argue those draftings were motivated by an organized anti‑Muslim campaign; proponents insist the model language is religiously neutral and meant to preserve constitutional primacy, a dispute that informs both the factual record courts considered and the public‑interest narratives around the litigation ^{[6] [7]}.

5. Why some later bills avoided outright mention of Sharia — and how that mattered in court

Recognizing constitutional exposure, many later statutes avoided explicit mention of Sharia and instead banned undefined “foreign laws,” an approach intended to evade First Amendment scrutiny but criticized as functionally indistinguishable and still vulnerable because courts must consider whether legislation targets a religion in purpose or effect and whether it creates unworkable vagueness for judges ^{[8] [4]}.

6. Limits of the record and where litigation did not always succeed

The available reporting documents the Oklahoma litigation as the clearest court victory and catalogs a wave of copy‑cat bills and failed proposals, but it does not provide a comprehensive list of every suit or every final appellate outcome in all states; reporting by the ACLU, academic law reviews, and legal commentators identifies constitutional flaws and practical dangers in many measures but does not claim that every state ban has been struck down ^{[1] [4] [9]}.

7. Takeaway: what drove judicial success and what remains vulnerable

Courts struck down the most legally exposed bans where challengers could show the measures explicitly targeted a religion, lacked any demonstrable governmental need, and risked constitutional and practical harms — while proponents’ claims of religious neutrality (as defended by ALAC’s author) and state assertions of protecting constitutional supremacy defined the adversarial record; the constitutional principles that prevailed in Oklahoma and in commentary remain the nucleus of successful challenges to similar laws ^{[2] [6] [7]}.