There is a certiorari petition before the Supreme Court on the question of whether or not bringing a drug sniffing dog to somone's home counts as a police search. It is a legal problem at all because using drug sniffing dogs on a person's car has been deemed "not a search" under the 4th amendment. This is a surprising result in itself, but leave that aside for the moment. So having discovered that using a drug sniffing dog around a car isn't a search, some police officer decided to use it around a house. This ends up implicating all sorts of problems, because constitutionally speaking homes are specially protected areas when it comes to police searches.
So now various high courts have to decide how to distinguish the case of the drug sniffing dog near a home from a drug sniffing dog near a car. Great. But that is the wrong question entirely. It turns out that drug sniffing dogs have an incredibly high false positive rate--they alert many more times than drugs are actually found once a search is done. Worse the dogs seem to alert much more often if their handler suspects there should be an alert--independent of whether or not there are actually drugs present. So the dog launders the police officer's suspicion instead of actually adding new information.
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