Hmmm... The Supreme Court looks to do damage to the Fourth Amendment as well. While they make the argument that dogs sniffing luggage at airports is OK, I don't think it is. Besides, the main difference between airports and hiways is that the dogs are sniffing to protect the safety of the passengers on the plane - hiway stops have no such wide ranging public benefit (of course, if you believe drugs are a moral crime, then you won't believe that either).
KR Washington Bureau | 11/10/2004 | Supreme Court hears case on drug-sniffing dogs' role in searches