Steve Ryan, a lawyer for the tax-preparation industry who negotiated a deal that has the IRS promising not to set up its own Web portal for e-filing, says his argument was simple. "When the government becomes my competitor," Ryan says, "then I have every right to run an ad that says 'Big Brother is watching your keystrokes.'"
http://www.npr.org/templates/story/story.php?storyId=9112083 I nearly choked when I read that. "Big Brother is watching my keystrokes"?! WTF? Of course they are, that's the point. They're not just watching, they're recording every value I enter into the form, so they can keep it in a file with my name, address, and social security number on it, and then use against me in a court of law! They get the exact same information if I use TurboTax, the only difference is TurboTax gets to watch my keystrokes, too, and then charge me for the privilege.
No, traditionally "the location of your car, driving around in public places" is not reasonably considered private. ("A person traveling in an automobile on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another." United States v. Knotts, 460 U. S. 276, 281 (1983)). The interesting thing about Justice Sotomayor's concurrence is that she left the door open to revisiting this in a future case. ("[B]ecause GPS monitoring is cheap in comparison to conventional surveillance techniques and, by design, proceeds surreptitiously, it evades the ordinary checks that constrain abusive law enforcement practices: limited police resources and community hostility." Slip. Op. concurrence at 3 (citation omitted)). She ultimately agreed with Justice Scalia that because there was an actual physical trespass here, the Court didn't need to reach that. ("We may have to grapple with these “vexing problems” in some future case where a classic trespassory search is not involved and resort must be had to Katz analysis; but there is no reason for rushing forward to resolve them here." Maj. Op. at 12.)
Traditionally if you were walking around on a public street you would expect that it would be possible for you to run into one of your friends, acquaintances, co-workers, or indeed, a police officer. If you were on your way to or from robbing a bank when that happened and that person ended up being a witness against you, you would call it bad luck, but you wouldn't say it was unreasonable invasion of privacy by the state: although possible, the improbability being meaningfully observed while in public colored our expectation of privacy. The police could follow your every public movement, of course, but the crushing cost of paying officers to follow you round the clock is beyond what most police departments could afford for any but the most serious offenders.
However, with omnipresent surveillance cameras, gps-enabled devices, and complete electronic records of our every transaction, we are fast leaving the realm where your public movements' being observed could be chalked up to bad luck and entering the era where the state can know everything about you with minimal cost or expense. And from reading this opinion, it seems like all the justices are in agreement that they are going to have to grapple with this soon.
To reiterate, I think war is unlikely, even if all of those things were to happen. But I think it's important to realize that just because war is not a rational decision doesn't mean it can't happen. Things have a way of spiraling out of control when you don't expect it.