United States v. Sullivan
[1] The case also served as the legal test for prosecution of Al Capone for tax evasion by Assistant Attorney General Mabel Walker Willebrandt.[2] In the 1920s, during the Prohibition Era, the successful prosecution of prominent organized crime bosses was nearly impossible because of witness intimidation and the lack of written records.Mabel Walker Willebrandt, then an Assistant Attorney General in charge of enforcing the Volstead Act, recognized that the figures publicly led lavish lifestyles but never filed tax returns and so might be prosecuted for that failure without testimony being required about the specific crimes that enriched them.Sullivan's lawyers argued that filing a tax return on illegal income would amount to self-incrimination and so he was therefore protected by the Fifth Amendment.Holmes dispatched another objection: It is urged that, if a return were made, the defendant would be entitled to deduct illegal expenses, such as bribery.