Most experts doubt the validity of polygraph tests as a means of determining whether or not someone is actually telling the truth. Polygraphs are useful in attempting to get someone to tell the truth—hook up a criminal suspect to enough electronic diodes and tell them a beeping machine can read their mind, and they'll say things they wouldn't otherwise. Usually, though, the polygraph machine is just a prop. Polygraph evidence is inadmissible in court-martial cases, and the Supreme Court is famously cool with that. Polygraphs test for physiological indicators that usually correspond to the physical stresses of lying, but don't always, and the test would be especially suspect in the case of someone who whose body is famous, above all, for responding to stresses differently than most people's bodies.
So when Lance Armstrong's lawyer brings up the possibility of a lie detector test, what he's really saying is that his client is so innocent and so confident of his own innocence that he could pass a lie detector test, if there really was such a thing. It's a pretty simple maneuver—you throw it out there, the people that believe polygraph tests are inviolable nod their heads and think, "Well, if he's confident he could pass a lie detector test, he must be innocent," and it never happens, because no official judicial procedure would consider a polygraph relevant in Armstrong's case. If there ever is one.
Which is what makes it so odd that Armstrong's lawyer allowed the possibility, and then undermined that sham confidence by saying there's no point, because no one would believe Armstrong anyway, so it won't happen:
Armstrong has always denied he took banned substances during his glittering career but refused to challenge the USADA charges against him.
His lawyer Tim Herman told the BBC's Radio 5 Sportsweek on Sunday that the Texan cyclist might take a lie detector test to prove his innocence.
"We might do that, you never know," Herman said, although he admitted that public perception of the American would be hard to change whatever the result of such a test.
The public perception of the American is so easy to change—even floating the lie detector possibility, without the second part, probably would have made a dent. Stacking the deck against yourself by saying that the public has made up its mind is a time-honored tradition, but if Team Lance is going that direction already, Armstrong might need a new lawyer. The lie detector thing makes you look confident, in a stupid sort of way—immediately backing down makes you look afraid.