In United States v. Dreyer, the US Court of Appeals reversed the conviction of a child pornographer because of the manner in which the government collected the evidence that was used to convict him. You can read the opinion here: http://cdn.ca9.uscourts.gov/datastore/opinions/2014/09/12/13-30077.pdf Standing alone, this isn't news; convictions get reversed all the time because the government violated somebody's Fourth Amendment rights. But this was not a Fourth Amendment case.
A detective with the Naval Criminal Investigative Service (yes, the same agency with a television program starring Mark Harmon) found a computer program that allowed him to search every computer in the State of Washington. Yes, you are reading correctly, and no, that is not a typo. Every computer in the State of Washington. Let that sink in for a minute. If you live in Washington, and have a computer, it was probably searched without your knowledge or consent by an employee of the US Department of Defense.
The agent found child pornography on a computer belonging to Michael Dreyer, who lived in suburban Seattle. Based on that evidence he was arrested, convicted of child pornography, and sentenced to prison.
Now, I yield to no one in my contempt for people who exploit children. I'm fine with locking child pornographers up and throwing away the key. But that is not the point.
There are few things I find more outrageous than child pornography, but the idea that somebody who works for the Pentagon can search every computer in an entire state, without a warrant, is one of them.
Fortunately the Court of Appeals saw it that way too, and tossed Dreyer's conviction. They did so, not on Fourth Amendment grounds, but on the basis of a statute that says the military cannot be used for normal, run of the mill law enforcement. The government is outraged and is promising an appeal to the Supreme Court. I don't see that that gets the government anything, because even if the Supreme Court agrees with it on the statute, I don't see how such a search clears the Fourth Amendment; since the Court of Appeals ruled on statutory grounds they did not reach the Fourth Amendment issue. They almost certainly will reach the Fourth Amendment issue if the Supreme Court sends it back.
But the troublesome take home message is that the government not only has the technology to go snooping around in anyone's computer they take an interest in, with no warrant, they already have. Further, the government is taking the position that they have the right to.
Fortunately, as of now, the courts have smacked them down. This is the sort of police state tactic that needs to be smacked down, and hard.