26 USC 5117 - Prohibited purchases by dealers

(a) General 
It shall be unlawful for any dealer to purchase distilled spirits for resale from any person other than
(1) a wholesale dealer in liquors who has paid the special tax as such dealer to cover the place where such purchase is made; or
(2) a wholesale dealer in liquors who is exempt, at the place where such purchase is made, from payment of such tax under any provision of this chapter; or
(3) a person who is not required to pay special tax as a wholesale dealer in liquors.
(b) Limited retail dealers 
A limited retail dealer may lawfully purchase distilled spirits for resale from a retail dealer in liquors.
(c) Penalty and forfeiture 
For penalty and forfeiture provisions applicable to violation of subsection (a), see sections 5687 and 7302.
(d) Special rule during suspension period 
Except as provided in subsection (b) or by the Secretary, during the suspension period (as defined in section 5148) it shall be unlawful for any dealer to purchase distilled spirits for resale from any person other than a wholesale dealer in liquors who is required to keep records under section 5114.