Fact check: How do federal laws (e.g., across state lines or on military bases) interact with state age of consent laws?

1. What the original claims say — clear, contested, and consequential

The analyses provided make three central claims: first, federal statutes frequently impose an 18‑year baseline for offenses involving interstate travel or communications with minors regardless of lower state ages of consent; second, military law can set a different age standard (notably a 16‑year threshold under the UCMJ) and relies on mechanisms like the Assimilative Crimes Act to incorporate state law on installations; third, federal child‑exploitation statutes criminalize production, distribution, and coercion involving minors on federal lands or in interstate commerce, creating independent federal jurisdiction even where state law might not reach ^{[1] [4] [2] [5]}. These claims overlap but differ on scope: some federal statutes target sexual conduct broadly tied to interstate elements, while others focus specifically on exploitation, transport, or communications.

2. The interstate baseline: federal reach when state lines or communications are involved

Federal statutes create national criminal boundaries when the conduct involves interstate travel, transportation, or communications, and those hooks often use 18 as the operative age for prohibitions tied to enticement, grooming, or transportation for sexual activity. Analyses note statutes like 18 U.S.C. § 2423 (transportation of minors) and sections criminalizing the use of interstate communications to entice minors, which apply even if both states involved set a lower age of consent ^{[6] [4] [7]}. The practical result is that a consensual relationship that is lawful under a state statute can still trigger federal charges when interstate elements or federal statutory targets (like online enticement or crossing state lines) are present, creating a legal divergence between state permissive rules and federal prohibitions.

3. Military installations and the UCMJ: a different federal frontier

Military law and jurisdiction over bases introduce a distinct legal regime. The Uniform Code of Military Justice, as summarized in the provided analysis, sets an effective age threshold at 16 for service members, lacks a close‑in‑age exemption, and operates under federal legislative jurisdiction on many installations. The Assimilative Crimes Act allows federal authorities to import host‑state criminal laws into federal prosecutions on federal lands when no federal statute directly addresses the conduct, so on‑post prosecutions can look like state law or UCMJ law depending on the gap‑filling and jurisdictional arrangements ^{[2] [8]}. Status‑of‑forces agreements and retrocession of jurisdiction permit concurrent or transferred authority, meaning civilian state courts can sometimes prosecute service members if the federal government allows it, but the baseline is federal control that may impose harsher penalties or different age rules.

4. Child exploitation statutes: production, distribution, and federal land hooks

Federal child‑exploitation statutes — including provisions criminalizing production, transportation, or distribution of sexually explicit material involving minors — operate with clear interstate or federal‑land triggers. These laws criminalize use of interstate commerce, and the statutes specifically apply to activities on federal lands, which includes military bases. The analyses emphasize statutes like 18 U.S.C. §§ 2251 and 2252 and the Department of Justice guidance that federal law often applies to conduct occurring on federal territory or involving interstate commerce, even when the underlying sexual conduct would otherwise be governed by a state age‑of‑consent rule ^{[5] [7] [3]}. Where federal exploitation statutes apply, state consent rules become secondary to federal prohibitions designed to address trafficking and production harms.

5. How state law is folded in — Assimilative Crimes Act and concurrent jurisdiction

The Assimilative Crimes Act functions as the legal bridge permitting federal courts to apply state criminal statutes on federal lands when no federal law addresses the precise conduct. The provided analyses describe how this leads to a patchwork outcome: some on‑post sexual conduct may be prosecuted under federal law modeled on state statutes, while other conduct is prosecuted under explicit federal statutes or under the UCMJ for service members. Concurrent jurisdiction arrangements and retrocession can shift cases to state juvenile or family courts, preserving state‑centered protections, but absent such agreements, federal prosecution remains the default on exclusive federal jurisdiction lands ^{[8] [9] [6]}. The practical effect is that venue and prosecutorial discretion determine whether state or federal age standards ultimately govern a given case.

6. Practical implications and what’s often omitted from brief summaries

Summaries that state “federal law sets an 18‑year age of consent” omit crucial nuances: federal statutes target specific activities tied to interstate commerce, transport, exploitation, or federal land; the UCMJ sets a different standard for service members; and the Assimilative Crimes Act allows state law to be imported into federal prosecutions on federal lands. The analyses collectively show that legal outcomes depend less on a single national age and more on the statutory trigger, the location (federal land vs. state), and jurisdictional agreements ^{[4] [2] [3]}. For practitioners and individuals, the safe takeaway is that crossing state lines, using interstate communications, involving federal property, or interacting with military personnel can change which laws apply and may expose parties to federal prosecution despite state consent ages.