This is journalistic fraud
Summary: Discussing Sen. John McCain's false claim that Iranian operatives are "taking Al Qaeda into Iran, training them and sending them back," CNN's Wolf Blitzer falsely asserted that McCain "quickly corrected [it] after some prodding from his Senate colleague, Joe Lieberman." Blitzer then aired a spliced video of McCain's misstatement immediately followed by his "correct[ion]." In fact, as The Washington Post reported, it was later in the press conference when McCain was "[p]ressed to elaborate" on his claim and after he reiterated that "Al Qaeda is going back into Iran and receiving training and are coming back into Iraq from Iran," that Lieberman "stepped forward and whispered" in his ear. McCain then corrected himself.
via many bloggers.
OK How long did those "few moments" last ? McCain made the claim twice. The first time, as shown on CNN was separated from the correction by more than a few moments, by a reporter questioning McCain's claim and by McCain insisting that it was "common knowledge."
CNNs version is inconsistent with the facts, so they decided to suppress them by editing out the part of the video which proves that McCain's claim that he immediately corrected himself is a lie.
mediamatters has a great catch, but their embed video tag doesn't work.