Caminetti v. United States
The Supreme Court upheld the convictions of three men who transported women across state lines not for prostitution or money, but so the women would become their mistresses, ruling that the federal White Slave Traffic Act's ban on transportation for "any other immoral purpose" was not limited to commercial sex trafficking.
The decision read the 1910 law's text broadly despite evidence that Congress mainly intended to target paid trafficking rings, establishing that plain statutory language controls even over a law's title, legislative history, and a strongly-worded dissent warning of blackmail abuse.
“There is no ambiguity in the terms of this act.”
The majority's basis for reading the law's ban on transportation for 'any other immoral purpose' literally.
How it got here: Each man was convicted and sentenced in federal district court; the respective Circuit Courts of Appeals affirmed; the Supreme Court granted certiorari and consolidated the three cases for one opinion.
The Case in Depth
What happened
Three men — Caminetti, Diggs, and Hays — were convicted under the 1910 White Slave Traffic Act (Mann Act) for arranging interstate travel by women they intended to make their mistresses or induce into "immoral practices." None of the cases involved payment or commercial prostitution; the women traveled to become companions or lovers of the men involved, not to be sold for sex.
The question before the Court
Did a federal law banning interstate transport of women for "any other immoral purpose" cover non-commercial affairs, like transporting a woman to become someone's mistress, or only paid prostitution?
Why it matters
The ruling meant federal prosecutors could pursue interstate travel connected to any extramarital or "immoral" sexual relationship, not just organized prostitution rings, dramatically widening the law's reach. For decades afterward, the broad reading enabled prosecutions of purely personal, noncommercial relationships and, as the dissent warned, created opportunities for blackmail threats tied to interstate travel.
What changes now
This is a final merits decision; the convictions and sentences of Caminetti, Diggs, and Hays stand as affirmed by the lower appellate courts. The broad reading of "any other immoral purpose" became the governing interpretation of the Mann Act, and the dissent's warning about blackmail and overreach did not change the outcome. Any future narrowing of the statute would require either Congress amending the law or a later Supreme Court decision revisiting this interpretation.
What this does not decide
The Court did not decide whether Congress could punish someone merely for traveling interstate while privately intending to commit an immoral act later; it stressed the law instead targets the actual transportation of a woman for the prohibited purposes, not bare travel with a bad intent.
Concurrences and dissents
Dissent — Justice McKenna
“There is danger in extending a statute beyond its purpose, even if justified by a strict adherence to its words.”The dissent's warning against reading the law more broadly than Congress intended.
Justice McKenna argued the statute's own title, "White-slave traffic Act," and the House committee report show Congress meant only to target commercialized, mercenary vice — paid trafficking — not private noncommercial affairs. He pointed to a 1912 Attorney General opinion declining to prosecute a similar noncommercial case as confirming this narrower purpose. He warned that the majority's broad reading invited blackmail schemes and swept in "occasional immoralities" Congress never meant to criminalize, and would have construed the statute more narrowly to serve its stated purpose.
How the Court got there
The legal reasoning, step by step
- The Court applied the plain-meaning rule of statutory interpretation: when a law's words are clear and Congress had constitutional authority to pass it, courts must enforce the text as written rather than search for a different meaning.
- Reading the statute's text, the Court found the ban on transporting a woman for prostitution, debauchery, or "any other immoral purpose" was not limited to cases involving payment or commercial vice; nothing in the operative sections required proof of financial gain.
- The Court relied on its earlier decision in United States v. Bitty, which held that a similar phrase in an immigration law covered bringing a woman into concubinage, not just prostitution for hire, reasoning that concubinage belongs to the same general class of immoral conduct.
- The Court rejected the argument that the law's short title ("White-slave traffic Act") and the House committee report describing commercialized vice should narrow the statute's plain words, holding that titles and legislative reports cannot override unambiguous statutory text.
- Turning to the trial issues, the Court held that once a defendant voluntarily testifies in his own defense, a trial judge may instruct the jury that it can draw an unfavorable inference from his failure to explain incriminating facts within his knowledge, without violating his privilege against self-incrimination.
- The Court also held that a trial judge is not required to give a special cautionary instruction that accomplice testimony must be corroborated, since no absolute rule bars convictions based on accomplice testimony that the jury chooses to believe.
Doctrinal impact
Cases affected by this decision
Reaffirms United States v. Bitty (208 U.S. 393)
Used to confirm that transporting a woman to become a concubine or mistress counts as an 'immoral purpose.'
Reaffirms Hoke v. United States (227 U.S. 308)
Relied on to confirm Congress had constitutional power to pass the Mann Act under the Commerce Clause.