Prohibition-era USA was, if not failed, at least a failing society. There was by this point pretty widespread public corruption and general lack of respect for the law.
Anyway, wasn't the tax evasion also an actual crime? It's not like you get a pass on the tax evasion because you're also strongly suspected of committing much worse crimes, is it?
> It's not like you get a pass on the tax evasion because you're also strongly suspected of committing much worse crimes, is it?
Tax evasion is what did Al Capone in. Because the bar to prove that he was involved in a lot of seriously criminal activity was quite high, but proving that he committed tax only required proving that he had undeclared income.