In the case of Florida v. Jardines (2012), the U.S Supreme Court ruled in favor of Joelis Jardines, stating that using a drug-sniffing dog on his porch constituted a search under the Fourth Amendment. The police had received an unverified tip about potential marijuana growth at Jardine's residence and used a K-9 unit to investigate without obtaining a warrant first. The dog alerted officers to the presence of drugs, leading them to secure a warrant and discover marijuana plants inside his home. However, Justice Antonin Scalia delivered the opinion for 5-4 majority court ruling that this was unconstitutional as it violated privacy rights protected by Fourth Amendment against unreasonable searches and seizures since they physically intruded upon private property -Jardine's front porch- with intent to gather information.

In the dissenting opinion for Florida v. Jardines, Justice Samuel Alito disagreed with the majority's decision that a drug-sniffing dog on a homeowner's porch constituted an unreasonable search under the Fourth Amendment. He argued that police officers should not be considered trespassers when they approach a home to knock on its door, as this is customary practice in American society and does not infrive upon any reasonable expectation of privacy. Furthermore, he contended that using a trained narcotics-detection dog did not transform this socially acceptable behavior into an unconstitutional invasion of privacy because dogs have been used for centuries to detect scents humans cannot perceive. Therefore, according to Justice Alito’s view, no illegal search occurred in this case since there was no physical intrusion into Jardines' home or violation of his reasonable expectations of privacy.