In the United States v. Jerry J. Nachtigal case of 1992, the Supreme Court examined whether a police officer's subjective intentions affected the Fourth Amendment reasonableness of traffic stops and vehicle searches. The defendant, Jerry Nachtigal was stopped for speeding by an officer who intended to use this as a pretext to search his car for drugs based on information received earlier from an informant. Upon searching the vehicle after obtaining consent, marijuana was found in large quantities leading to Nachtigal’s arrest and subsequent indictment on drug charges. Nachtigal moved to suppress evidence obtained during this stop arguing that it violated his Fourth Amendment rights because it wasn't conducted with proper intent but rather as a pretext for drug investigation without probable cause or reasonable suspicion. The Supreme Court ruled against him stating that so long as officers have objective justification (in this case, speeding) for their actions under standard law enforcement practices; their underlying motivations do not invalidate those actions under the Fourth Amendment.

In the dissenting opinion for United States v. Jerry J. Nachtigal, Justice Blackmun disagreed with the majority's decision to uphold Nachtigal's conviction on charges of assaulting a federal officer and resisting arrest. He argued that there was insufficient evidence to support these convictions because it was unclear whether the officers involved were acting in their official capacity at the time of the incident, as required by law for such charges to be valid. Furthermore, he contended that even if they were acting officially, there was no proof that Nachtigal knew this fact when he resisted them - another necessary element for his conviction under current statutes. In conclusion, Justice Blackmun believed that upholding Nachtigal’s convictions without clear evidence supporting all elements of his alleged crimes undermined fundamental principles of justice and fair play.