"How can you tell if a politician is lying?"
"His lips are moving."
If one thing is certain coming out of the Clinton email fiasco, it's that Hillary is a liar. Okay, nobody is surprised. Is it on the same level as "I didn't have sex with that woman?" Actually, it is, pretty much. Like Bill, Hillary told lies of expediency, aimed at diverting immediate blame. It's kind of on the same level as "The dog ate it."
Unlike Hillary, Tr*mp actually seems to believe his lies as he tells them — then believes his contradictions the next day. It strikes me, at least, as pathological.
Boris Johnson and Nigel Farage told a number of major whoppers in their campaign for the Brexit vote, most notably about the amount of money the UK would save by withdrawing from the EU, and the idea that said money would be used to shore up the National Health Service. Both of them, however, had the good grace to duck out of the way when their lies were uncovered.