It can never be pointed out often enough that there IS a reliable way to tell if a politician is lying: His lips are moving:
The more you lie, the easier it gets - health - 08 February 2011 - New Scientist: "'In people who lie a lot in real life [such as pathological liars], this dominant truth response might not be as strong as we theorise,' says Ewout Meijer of Maastricht University in the Netherlands.And now we have emerging scientific evidence. RTWT.
Crucially, says psychologist Scott Lilienfeld of Emory University in Atlanta, Georgia, the results raise the intriguing possibility that at least some lie detector measures may be relatively ineffective for practiced liars, including psychopaths. 'Lie detector tests are most often used on people suspected of crimes, who have higher rates of psychopathic characteristics – including pathological dishonesty – than other individuals,' he says.
'The finding implies that peppering a lie-detector test with simple questions designed to elicit a truthful response will strengthen the brain's truth response, making it harder for someone to lie. This will increase the accuracy of such tests,' says Meijer."