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. It was amended by Congress in 1978 and again in 1986 to limit its application to transport for the purpose of prostitution or other illegal sexual acts.