A bald assertion

"The media this year are really in the tank for liberals."

"That, sir, is a boldfaced lie."

Sorry, that's the first think I thought of when I read this:

Yesterday Jr. Illinois Senator Obama told a bold-faced lie on the stimulus package. Not only did he not have a role in formulating the legislation, he didn't even bother showing up to vote on it.

Actually, though "baldfaced" is the most commonly used, "boldfaced" isn't exactly wrong, nor is "barefaced." Here's a fascinating history of the phrases by William Safire, who also notes that the original meaning of bald was "white," hence bald eagle (the white feathers) and Old Baldy, the term for horses with white markings on their noses.