How have lower federal courts interpreted 8 U.S.C. §1373 and §1644 in cases involving sanctuary jurisdictions?

1. Historical anchor: Second Circuit’s 1996 posture and its limits

The Second Circuit’s 1996 decision refused a broad constitutional invalidation of §§1373 and 1644 and read the statutes narrowly as forbidding local rules that restrict voluntary information-sharing while not commanding local officials to enforce federal immigration law, a framing that anchored early lower-court interpretations ^{[1] [2]}.

2. The funding battlefield: courts reject DOJ grant conditions

When the DOJ in the Trump administration tied eligibility for Byrne JAG and other grants to compliance with §1373 and related cooperation terms, multiple federal courts treated those funding conditions as unlawful — finding they constituted unconstitutional or impermissible conditions on federal grants — and enjoined the government’s effort to cut funding for “sanctuary” jurisdictions ^{[4] [2] [5]}.

3. A district court breaks ranks and declares §1373 unconstitutional

A notable district-court opinion in City of Philadelphia v. Sessions concluded that §1373 was itself unconstitutional, reasoning that the statute improperly restrained state and local governments in a manner analogous to other impermissible federal intrusions on state authority; that ruling marked a departure from earlier deference to the statute’s validity ^[3].

4. Anti-commandeering and preemption debates: lower courts split

Lower courts have repeatedly wrestled with whether §§1373 and 1644 are preemptive federal law, permissible regulatory limits, or unconstitutional commandeering of state functions; courts have explicitly disagreed on whether the statutes impermissibly commandeer local governments, with some analyses finding the statutes run afoul of anti-commandeering principles and others viewing them as narrow limits on local ordinances ^{[1] [6] [2]}.

5. Scope disputes: what information and what duties?

A recurring point in the caselaw is textual scope — whether §§1373/1644 cover only “information regarding citizenship or immigration status” and thus leave release dates and detainer practices untouched — and lower courts have cited that ambiguity in holding that many sanctuary policies do not violate the statutes because the laws do not impose affirmative duties to collect or share information ^{[7] [8] [6]}.

6. Regulatory enforcement vs. criminal coercion: how courts treated executive orders

Judicial scrutiny has also targeted executive attempts to use executive orders and DOJ guidance to coerce compliance; courts have found that conditioning federal grants or demanding certifications of compliance strays beyond lawful executive implementation of §§1373/1644, prompting injunctive relief against DOJ and DHS practices in multiple cases ^{[4] [5] [7]}.

7. Competing narratives and institutional agendas in the lower-court record

The litigation record reflects competing institutional agendas: the Department of Justice and proponents argue §§1373/1644 are essential to national immigration enforcement and that conditioning funds is lawful, while cities, advocacy groups, and some courts emphasize local autonomy, public-safety rationales for sanctuary policies, and constitutional limits on federal coercion — perspectives that shape divergent rulings across districts and circuits ^{[9] [6] [8]}.

8. Present landscape and limits of the lower-court canon

The net of lower-court decisions is fractured: some rulings affirm the federal government’s leverage, others block funding conditions or invalidate §1373 in specific cases, and courts continue to differ on scope and constitutional questions; sources reviewed do not purport to catalog every district- or circuit-level disposition or any post-2025 Supreme Court resolution that might resolve the splits ^{[2] [3] [1]}.