Illegal activities did become more of a concern by the 1920s and 1930s, but not quite in the same ways as today. What types of smuggling took place along the border in the early 1900s and how did each nation attempt to address it, for example? Vice and drinking became a draw that brought US citizens southward into Mexican border towns during Prohibition, as St John describes in Chapter 6. How did officials along the border respond to those developments?