Defendant was arrested in Cambodia for sexually abusing minor children, and was convicted of violating 18 U.S.C. s. 2423(c), which prohibits engaging in illicit sexual conduct in foreign places. Defendant challenged the constitutionality of s. 2423 (c), which applied to a US citizen "who travels in foreign commerce". In a previous case, the Ninth Circuit held that the illegal conduct did not have to occur while traveling, and it was sufficient that the person traveled and then committed the illegal conduct. See United States v. Clark, 435 F.3d 1100, 1107 (9th Cir. 2006).
In 2013, however, Congress amended s. 2423(c) to say "who travels in foreign commerce or resides . . . in a foreign country". Based on the addition in the statutory language, the court held that the statute would not apply to the defendant if he took residence in Cambodia rather than was traveling in the country. Accordingly, the court vacated the conviction and remanded.
This appears to be the correct result, although the consequences can be difficult to stomach. It's an object lesson for the legislature to draft the statute with more care.