Resale price maintenance.
wUnited States v. Colgate & Co. (1919).
nA manufacturer is free (1) to announce a policy of refusing to sell to dealers who fail to charge suggested RP and (2) to terminate nonadhering dealers.
wUnited States v. General Electric Co. (1926).
nDealer is a consignee of the manufacturer and therefore the manufacturer's agent rather than a purchaser.  Not technically a "restraint on alienation," since dealer never owned the goods.
Loopholes.