§ 56. Employer's failure to withhold.--If an employer fails to deduct
and withhold tax as required, and thereafter the tax against which such
tax may be credited is paid, the tax so required to be deducted and
withheld shall not be collected from the employer, but the employer
shall not be relieved from liability for any penalties, interest, or
additions to the tax otherwise applicable in respect of such failure to
deduct and withhold.