It won't be the last word on the issue, but the court took an important step toward reconciling the growing clash between 21st-century technology and the Constitution's 18th-century protection against unreasonable searches - the Fourth Amendment.
Legal observers say the justices' ruling indicates they might be willing to apply the same constitutional safeguards against a broad range of digital technologies. That's entirely appropriate, since consumers who use cell phones, E-ZPass tags, highway emergency-alert services, or other technologies that identify their location certainly are not willingly surrendering their right to privacy.
Yet, the ability of authorities to tap into this information has leapfrogged ahead of traditional procedures police use in seeking court approval for a search warrant. So, while some police and prosecutors already err on the side of caution by obtaining warrants for all tracking devices, that should be established as the standard by law.
There's nothing inherently wrong with using space-age tracking devices under a warrant, providing a court finds a compelling need to thwart criminal activity or safeguard the public. But surveillance must be monitored carefully, and limited to crime-fighting efforts.
The Supreme Court's decision also indicated it might be best if Congress - rather than the courts, in piecemeal fashion - settled the privacy issues raised by new tracking technology and other techniques, such as video surveillance in public areas.
Indeed, if this issue somehow were able to skirt the partisan gridlock that has stymied Washington, Congress might once and for all restore to citizens the rightful expectation that Big Brother isn't watching their every move.