If the government places a surveillance device in your home, is that sufficiently like quartering troops there to trigger Third Amendment scrutiny? What if it installs spyware on your computer or your cable modem? What if it requires “smart meters” that allow moment-to-moment monitoring of your thermostat settings or toilet flushes?

The famous birth-control case of Griswold v. Connecticut invoked the Third Amendment, along with several others, with the Court asking, “Would we allow the police to search the sacred precincts of marital bedrooms for telltale signs of the use of contraceptives? The very idea is repulsive to the notions of privacy surrounding the marriage relationship.” If physically searching the bedroom is “repulsive,” what about activating the camera on someone’s laptop for remote viewing? Or monitoring the “Skype sex” sessions of spouses who are apart? How could that possibly be less repulsive?

These specific concerns weren’t what the Framers had in mind. In their day, to spy on a family in its own home, you’d have to put a soldier there. But now we have electronic troops in the form of software, gadgets and sensors.