Who Supplied The Drugs

A man sold heroin twice to undercover federal agents. He says the drugs were never his: a paid government informant handed them to him and lined up the buyers, telling him it was easy money. The government says he knew perfectly well it was heroin and sold it willingly. He does not really deny he was willing. The question is whether it can be fair to convict a willing seller when the government itself supplied the drugs he sold.