In its original form the act made it a felony to engage in interstate or foreign commerce transport of "any woman or girl for the purpose of prostitution or debauchery , or for any other immoral purpose". Its primary stated intent was to address prostitution, immorality, and human trafficking , particularly where trafficking was for the purposes of prostitution.
It was one of several acts of protective legislation aimed at moral reform during the Progressive Era. In practice, its ambiguous language about "immorality" resulted in it being used to criminalize even consensual sexual behavior between adults.
In the 19th century, many of America's cities had designated, legally protected areas of prostitution ; and increased urbanization as well as greater numbers of young women entering the workforce led to greater flexibility in courtship without supervision.
It is in this changing social sphere that concern over "white slavery" began. This term referred to women being kidnapped for the purposes of prostitution. Numerous communities appointed vice commissions to investigate the extent of local prostitution, whether prostitutes participated in it willingly or were forced into it, and the degree to which it was organized by any cartel -type organizations. The second significant action at the local level was to close the brothels and the red light districts.
From to , city after city changed previously tolerant approaches and forced the closing of their brothels. Opposition to openly practiced prostitution had been growing steadily throughout the last decades of the 19th century. The federal government's response was the Mann Act. The purpose of the act was to make it a crime to "transport or cause to be transported, or aid to assist in obtaining transportation for" or to "persuade, induce, entice or coerce" a woman to travel.
