Recently, Orin Kerr and I had a brief conversation on Twitter regarding the Fourth Amendment and the content/non-content distinction. Specifically, Orin asked those of us who subscribe to the mosaic theory of intelligence if some large amount of metadata can become content, can some small amount of content become metadata by the same logic? That is, if non-content in sufficient quantities can become content under the Fourth Amendment, shouldn’t the inverse of this function mean that sufficiently small amounts of content can become non-content? (Remember that content receives great constitutional protection than non-content.) There is a fair amount of unpacking to do in this short question, so let’s start by exploring the mosaic theory as it applies to Fourth Amendment law.
Mosaic theory describes the idea that a sufficient quantity of small pieces of seemingly innocuous data, pieced together by a clever analyst, can develop into an intelligence picture whose importance can outweigh the sum of the individual parts — much like the intricate patterns found in ancient Mesopotamia, Greece, and Rome, for which the theory is named. It follows from this theory that seemingly unimportant scraps of information — e.g., metadata — that by themselves do not rise to meet the current definition of a Fourth Amendment search, could be compiled and analyzed in large enough quantities to yield an intelligence picture at least as (if not more) meaningful than what might have been possible by collecting content information, which would typically require a court-issued warrant. Mosaic theory adherents assert that this scenario depicts a loophole in Fourth Amendment doctrine, giving government agencies the ability to bypass warrant requirements altogether through advanced technologies performing big data analytics. Further, because these metadata are preformatted for computer consumption — requiring little, if any, massaging by human data technicians — the government is given a distinct advantage, severely tipping the balance of power between citizen and state. Sufficient amounts of under-the-radar non-content data would effectively become content, and should therefore receive appropriately greater protection under the Fourth Amendment.
Read the full piece at Just Security.