She would revisit the "reasonable expectations" doctrine, especially the part that supposes you have no privacy interest in information - like your car's path on public roads or telephone "metadata" - disclosed to third parties.
Civil libertarians celebrated Sotomayor's opinion, sensing a pro-privacy backlash at the Supreme Court - but I doubt it.
Yes, there's a difference between things we voluntarily publicize - like Snowden's pseudonymous musings about sex, etc. - and the digital bread crumbs we involuntarily leave for government and corporations to gather.
Still, Sotomayor seemed to take that point a bit too far. Quoting a lower court judge, Sotomayor alluded to "indisputably private . . . trips to the psychiatrist, the plastic surgeon, the abortion clinic, the AIDS treatment center, the strip club, the criminal defense attorney, the by-the-hour motel, the union meeting, the mosque, synagogue or church, the gay bar and on and on."
While all of these examples are potentially controversial, none is "indisputably" private by today's standards; church strikes me as usually pretty public, actually.
In another concurring opinion, Justice Samuel A. Alito Jr. doubted the constitutionality of lengthy warrantless GPS surveillance but noted realistically:
"New technology may provide increased convenience or security at the expense of privacy, and many people may find the tradeoff worthwhile. And even if the public does not welcome the diminution of privacy that new technology entails, they may eventually reconcile themselves to this development as inevitable."
Alito suggested that legislatures, not courts, should take the lead in defining privacy law, since they are better "situated to gauge changing public attitudes, to draw detailed lines, and to balance privacy and public safety in a comprehensive way."
Still, the only thing less workable than the "reasonable expectations" doctrine might be constant political attempts to account for what every individual might feel like broadcasting, or accept as "inevitable."
In 1929, Secretary of State Henry L. Stimson closed the State Department office that intercepted and decoded foreign diplomatic letters, explaining that "gentlemen do not read other gentlemen's mail."
We need rules for a generation that reads Stimson's words and wonders:
What's a gentleman? And what's mail?
Lane is a member of The Washington Post's editorial board.