This whole search for terrorist collaborators thing is getting a little ridiculous. Tapping into millions of domestic phone calls (and probably blogs and emails and IMs) in the name of terrorism? That's legal?
So, here's my nightmare scenario. If this is legal, the next step is to force functional MRIs on people to determine what they know (about terrorism, of course). The technology is there. Functional MRI (fMRI) measures minute changes in blood flow in the brain, comparing areas to see which ones have more blood flow, and thus are more active. It seems that one must use specific brain areas to make stuff up. This technology is being used for good purposes (eg, controlling chronic pain), but could certainly be applied to darker motives.
"Would the Court view an involuntary brain scan as a nonintrusive gathering of information rather than a search governed by the Fourth Amendment? Would the Court view brain scans as forcing an involuntary disclosure of thoughts prohibited by the Fifth Amendment's requirement that individuals not be made to testify against their will?"fMRI is not "invasive" in the classical sense. No needles. No tubes. Sorta like going through an airport scanner, but lying down (you can even keep your shoes on). So what's to stop them from using this technology on Gitmo detainees (or on us)?
The chronic pain link above is interesting, BTW. It makes me wonder if real-time fMRI scanning can be used to learn how to better control obsessive thoughts or auditory hallucinations or anxiety.