Discussing Sen. Joe Lieberman's (I-CT) scheduled appearance at the Republican National Convention during the September 2 edition of MSNBC Live, NBC News Washington bureau chief Mark Whitaker misidentified Lieberman as a “leading Democrat.” NBC News foreign affairs correspondent Andrea Mitchell also called Lieberman a “pariah in his own party.” In fact, after losing the 2006 Connecticut Democratic primary to challenger Ned Lamont, Lieberman re-launched his Senate campaign as an independent in August 2006 and went on to defeat Lamont in the general election. On January 12, 2007, Congressional Quarterly reported that “Lieberman has asked to be called an Independent Democrat,” and that “if the compound modifier that the senator prefers was not going to take hold, then Lieberman's second choice is to be described as an Independent.”

Media Matters for America has previously documented other instances in which media figures and news outlets falsely referred to Lieberman as a Democrat.

From the 1 p.m. ET hour of the September 2 edition of MSNBC Live:

WHITAKER: Well, we just got out of a briefing with top McCain people going through the schedule tonight, and what we're going to see is, first, George Bush coming remote from the White House, introduced by the first lady, and then followed by [former Sen.] Fred Thompson [TN] and Joe Lieberman, who are essentially going to tell the country why John McCain is not George Bush.

MITCHELL: And Joe Lieberman is a double-edged sword because his very presence here, first of all, historic -- Joe Lieberman never before addressed a Republican convention and now pretty much a pariah in his own party -- but it's a constant reminder just seeing him up here how close he came to being the vice-presidential pick.

WHITAKER: On the one hand, it's an extraordinary moment. I mean, the idea of a leading Democrat as well-known as Joe Lieberman, who was the vice-presidential candidate in 2000, now coming out to vouch for the Republican nominee, and someone who knows him so well. But as you say, we now know that until basically 10 days ago, John McCain really wanted Lieberman to be his vice president, and that, again, keeps alive this story of how quickly did they shift to Governor Palin? How well was she vetted?