Just like he lied that the driver of the truck that killed his wife and daugther was drunk.
The sad reality is that the Vice President of the United States is a chronic, unrepentant liar. There’s no polite way of saying it. The media pass it off as a “gaffe” or “Joe being Joe”, but it is intentional on Biden’s part and it is insidious. it is also long-standing. Here’s a reminder from the 1988 campaign when the Dukakis campaign torpedoed Biden:
“Democratic presidential candidate Joseph R. Biden Jr., a U.S. senator from Delaware, was driven from the nomination battle after delivering, without attribution, passages from a speech by British Labor party leader Neil Kinnock. A barrage of subsidiary revelations by the press also contributed to Biden’s withdrawal: a serious plagiarism incident involving Biden during his law school years; the senator’s boastful exaggerations of his academic record at a New Hampshire campaign event; and the discovery of other quotations in Biden’s speeches pilfered from past Democratic politicians.
The controversy became two frenzies in one when it was disclosed that the campaign of Massachusetts Gov. Michael S. Dukakis had earlier secretly distributed to several news media outlets an “attack video” juxtaposing the Biden and Kinnock speeches and revealing Biden’s word theft”
http://www.washingtonpost.com/wp-srv/politics/special/clinton/frenzy/biden.htm