In the 1992 case United States v. Lowell Green, the Supreme Court addressed whether a defendant could be convicted for conspiracy to distribute cocaine based on evidence of possession and distribution of marijuana. The court ruled that while there was sufficient evidence to convict Green for his involvement in a marijuana trafficking operation, there was insufficient proof linking him directly to any cocaine-related activities. Therefore, it concluded that he could not be held accountable for conspiring to distribute cocaine solely based on his proven association with marijuana distribution. This ruling highlighted the need for specific and direct evidence when charging an individual with conspiracy related crimes under federal law.

The dissenting opinion in the United States v. Lowell Green case argued that the majority's decision to uphold Green's conviction for conspiracy to distribute cocaine was based on insufficient evidence. The dissent contended that while there was evidence of a buyer-seller relationship between Green and his co-defendant, this alone did not prove a conspiratorial agreement to distribute drugs as required by law. It further noted that no additional corroborating evidence such as large quantities of drugs, scales or packaging materials were found at Green’s residence which could suggest an intent for distribution rather than personal use. Therefore, it concluded that without substantial proof demonstrating beyond reasonable doubt about the existence of a conspiracy between defendants, upholding such convictions would set a dangerous precedent potentially leading to wrongful convictions in future cases.