In each of these cases, the courts held that the warrantless tracking was exempt from the Supreme Court ruling because it was conducted before the ruling and because appeals courts in both the Eighth Circuit and the Ninth Circuit have previously permitted warrantless GPS tracking.

The same reasoning cannot be applied to Lee's case because there has been no similar precedent established by the Sixth Circuit Court of Appeal. "When carrying out searches, federal officers need only know the binding decisions of the Supreme Court and their circuit's court of appeals," Thapar noted.

In the absence of a precedent in the Sixth Circuit, the officers acted illegally when they attached the GPS tracker to Lee's car without a warrant, he wrote.

"The DEA agents in this case did not rely on any binding appellate precedent," Thapar wrote. "Neither the Sixth Circuit nor the Supreme Court had spoken on the issue of GPS surveillance when the agents placed the tracking device on Lee's car."

Lee was arrested in September 2011 on his way back to London, Ky. after a trip to Chicago. Lee had just completed a period of supervised release after a 42-month stint in prison on marijuana distribution and firearms possession charges.