My first post on the reliability of drug detection dogs was linked to by EvidenceProf Blog, where Colin Miller makes an excellent point about why quantifying probable cause may be more feasible than quantifying proof beyond a reasonable doubt. Although an artificial imposition of a numeric value on the proof beyond a reasonable doubt standard will likely confuse jurors, writes Miller, we believe in many contexts that judges are better equipped to navigate complex evidentiary matters.
Since judges- not jurors- decide whether probable cause justifies a particular search, quantifying probable cause might not unearth such a parade of horribles, the fear of which has imprisoned the probable cause standard in fuzziness for so long. We may need to quantify probable cause to decide if a positive alert by a drug sniffing dog gives the police enough suspicion to conduct a full search of a person’s car, or suitcase, or of the person’s person.
Let me be clear. I am not arguing (at least for now) that every probable cause determination should be calculated according to a mathematical algorithm where the evidence has to yield a certain likelihood of criminal behavior (40%?, 50%?, 51%?) before probable cause is satisfied. However, if the Supreme Court affirms the Florida Supreme Court’s holding that evidence of a dog’s false positive rate must be admitted as part of the probable cause inquiry, courts will have to grapple with some quantification of probable cause. Unless the Supreme Court decides that a positive alert by a drug detection dog is never, on its own, sufficient to establish probable cause, courts will confront situations where a dog’s positive alert is the sole reason to suspect someone of possessing drugs. This could occur at an airport, or at a drunk driving checkpoint, or anywhere where drug dogs are permitted to routinely sniff individuals without suspicion. In that case, courts will have to decide if the dog sniff alone is sufficient to establish probable cause.