Back in pre-Constitution America, the British army would burst into the homes and businesses of American colonists.
The searches would often be destructive, and intended so. Some of the time the point was to seize incriminating "revolutionary" materials, many times the point was simply to harass and threaten people the Crown feared and wanted to send a message to. It was in direct response to such invasions of freedom that the Founders wrote in the Fourth Amendment "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated..."
Posse Comitatus Act
Fast-forward to 1878, in the Constitutional America Era, when, in the wake of the Civil War, the Posse Comitatus Act was passed into law. The Act limited the power of the federal government to use the armed forces of the United States to enforce state laws, though the general interpretation evolved to limit severely the use of federal troops for law enforcement purposes.
While both Bush and Obama weakened the Act to allow for troops to deploy (Bush) domestically and arrest civilians (Obama) in the wake of terrorist acts, the general idea remains intact. There are plenty of law enforcement agencies, local and federal, around to enforce the law. When the home town cops can't handle it, the FBI can step in, not the military.
Old Rules Do Not Apply
Despite that clear background, it comes as little surprise that here in Post-Constitutional America, the old rules do not apply, even on a small scale.
Yet in perhaps a tiny but significant decision, an appeals court ruled federal authorities had shown "a profound lack of regard for the important limitations on the role of the military in our civilian society" when they allowed the U.S. Navy to scan the computers of every citizen in the state of Washington fishing for evidence, any evidence of any crime, that could be turned over to local cops. The court so wished to admonish the Navy's Criminal Investigative Service (NCIS) for overstepping regulations that have evolved from the Posse Comitatus Act that it took the unusually strong step of excluding the computer evidence in any new trial of a child pornographer. "The extraordinary nature of the surveillance here demonstrates a need to deter future violations," said the ruling.
What happened? An NCIS investigator charged with online surveillance allegedly to protect naval facilities in Washington state, determined that his scope included electronic monitoring of the whole state and its entire civilian population. Since Navy families had kids, and/or because Navy personnel could be child pornographers, the NCIS argued extending the surveillance away from terrorism to scanning for kiddie porn had a legitimate military-related purpose. It is unclear if the employee acted on his own with no supervision, or acted under orders; neither is a good scenario.
The NCIS spook set loose in Washington state with a computer tool called RoundUp on the Gnutella peer-to-peer network known to be favored by child pornographers to exchange illegal images. Gnutella allows a direct connection between multiple personal computers in lieu of a single server, so that tracking down and eliminating the "source" of files is much more difficult. The RoundUp software (a similar product is called GridCop) identifies computers on a peer-to-peer network by their individual Internet Protocol (IP) addresses. Investigators then work backwards to determine which service provider (such as Verizon) hosted the IP address and subpoena the provider for the name and address of the account holder. Investigators can then apply for and execute a search warrant for the computer and arrest the owner.
Tech Point: RoundUp works by detecting known child porn files that have been identified in investigations based on cryptographic hash algorithms, or hash values, which are unique numeric identifiers generated based on the content of digital files. Duplicate files will usually have the same hash value even if users rename files.
The FBI and local cops are doing this kind of thing all the time; the big deal in this case is that the agency at work is the U.S. Navy, which, under Posse Comitatus, is not supposed to be involved in such law enforcement. That is the illegal part, and the part that raises serious questions in an already nasty Post-Constitutional environment about what parts of the body of law the federal government will follow, and which parts it will ignore. That is not how a democracy works.
More on the Specific Case
The short version is that after actively monitoring the entire state for well, whatever it could find, the NCIS found one alleged child pornographer.
NCIS gathered evidence, turned it over to local police, who obtained a warrant based on the Navy search to legally "reacquire" the evidence (see also parallel construction, where the NSA and DEA use a similar illegal process.) The owner of the computer was convicted of possessing and distributing child pornography, and is now serving an 18 year sentence at a federal prison. He appealed, claiming the evidence against him was obtained illegally, and the court threw the evidence out. The case will likely be retried. Without the actual evidence of child porn images, prosecutors have little to work with. The feds may appeal the decision. The convicted man remains in jail
Nobody likes child pornographers. As a parent, I wish every one of them would be fully, legally prosecuted and punished. But before you say "Well, NCIS did a bad thing, but in the end a child pornographer may be let off scot-free, which is worse" remember it was in fact the illegal acts of the NCIS that tainted the evidence and which themselves will see the guy walk if that is what happens. Bad law enforcement does not create good results. Walking all over the law to enforce it does little good for our society, and outright contempt for the law, as exhibited by NCIS, is evil in a society that once claimed to be a democratic example to others of the rule of law.
"Letting a criminal go free to deter national military investigation of civilians is worth it," the judge in this case wrote. "[This] amounts to the military acting as a national police force to investigate civilian law violations by civilians."
Deterrence may indeed be the order of the day. The NCIS case above surfaced only after the specific person convicted appealed, and had legal help smart enough to ask where the evidence against him came from. We know nothing about the extent of NCIS spying on civilians in Washington state, whether or not this is NCIS policy, and whether or not such spying, rogue or not, takes place in other states with military facilities. The NCIS employee at fault in Washington did say a colleague in Georgia was doing the same thing, so there is reason to wonder outside of just raw speculation. Those might have been good questions for the judges who decided the case, or the journalists who covered it, to ask.
As for the NCIS, a spokeswoman declined to talk about whether the service has undertaken similar wide searches for child pornography offenders in other states with a significant Navy presence, like Florida, Virginia or California.
Lastly, there are law enforcement agencies directly charged with hunting down child pornographers, armed with the same tools or better than NCIS. The FBI comes to mind. So where were they while one NCIS person was free-lancing an assault on the Posse Comitatus Act and the Fourth Amendment?