At least they could use something like what has been used in India[1] (though many jurisdictions forbid its usage), at least there is some science behind it. However, because it’s science based and not just a bunch of “woo”, it has the inherent danger of being ”incontrovertible”. Kinda like DNA,but obviously flawed none the less.
My golly - the havoc that beast would wreak if applied to all officials! It would almost be worth unleashing on the public, if perfected from the top down. Though it never seems to work that way. I'm already lucidly envisioning future politicians murmuring very nervously through federally issued mandatory truth helmets.
Realistically, I truly wonder if the consummate versions of such tech won't become the keystone of the future world's pyrrhic utopia. In some paved global labyrinth of potted plants, designer integrity and perfect safety, where lies are only fiction of the past and dissidence is a vestigial dead synapse in the collective mind.
[1]http://theconversation.com/if-a-brain-can-be-caught-lying-sh...