"This fact sheet will explain the differences between human smuggling and human trafficking. Because these are complex crimes, it is not always readily apparent when a 'human smuggling' case crosses into the realm of a 'human trafficking' crime. Understanding the basic principals outlined in this fact sheet will assist the reader in identifying the subtle differences between each of these crimes. For this discussion, the terms 'human trafficking' and 'trafficking in persons' refer strictly to 'severe forms of trafficking' as defined in 22 USC 7102. As in any other area involving complex crimes, it is important to gather and examine as many relevant facts as possible, compare the fact pattern against relevant statutes, and when necessary, seek expert legal advice in making determinations."
U.S. Dept. of Justice: http://www.usdoj.gov/