What is the name of this crook?

Is it ok if someone reliably lies all the time ? Logically one can get the truth out of a reflexive liar by take a yes or no question Q and asking "If i were to ask you Q what would you say?"

I think journalists should try this with Romney. He lies more than I imagine possible even taking into account that he lies more than I imagine possible.

For example, he just broke down and admittedthat he pays about 15% of his income in taxes. I should have concluded that he doesn't pay about 15% of his income in taxes. Instead, I had to wait for the great Josh Marshall and Reuters (who are doing a great job lately) to explain to me that he probably pays much less by receiving incipome in tax paradises.
http://talkingpointsmemo.com/archives/2012/01/is_it_even_15.php?ref=fpblg

Mitt Romney should run for President of the Cayman islands where he pays his tiny taxes (don't tell him that they are a colony of the UK and don't elect their head of state -- Queen Elisabeth doesn't pay taxes at all).