William J. Brennan, Jr.

“ The privilege against self-incrimination does not bar the Government from establishing every program or scheme featured by provisions designed to secure information from citizens to accomplish proper legislative purposes. Congress is assuredly empowered to construct a statutory scheme which either is general enough to avoid conflict with the privilege, or which assures the necessary confidentiality or immunity to overcome the privilege. ”

“ The wagering excise tax, the occupational tax, and the registration requirement are only parts of an interrelated statutory system for taxing illegal wagers. Whatever else Congress may have meant to achieve, an obvious purpose of this statutory system clearly was to coerce evidence from persons engaged in illegal activities for use in their prosecution. ”

“ On the other hand, we know that where the governmental scheme clearly evidences the purpose of gathering information from citizens in order to secure their conviction of crime, it contravenes the privilege. ”