Republican strategist Karl Rove called Vice President Biden a "liar" on Thursday, dramatically escalating a feud between Biden and aides to former President George W. Bush over Biden's claims to have rebuked Bush in private meetings. "I hate to say this, but he's a serial exaggerator," Rove told FOX News. "If I was being unkind I would say liar. But it is a habit he ought to drop." Rove added: "You should not exaggerate and lie like this when you are the Vice President of the United States." Biden's office did not immediately respond to a request for comment, although...