Writing for Commentary‘s “Contentions” blog, Jonathan S. Tobin discusses the fallout from the Obama campaign’s decision to use a news clip of Andrea Mitchell in one of its advertisements.

NBC has reacted to this breach of the informal rules of engagement between liberal journos and the Obami with high dudgeon and has asked the Democrats to take the ad down. Much as they did when the president’s re-election campaign used a clip of Tom Brokaw, the network says that since they haven’t granted permission for the use of the material it ought not to be aired in the context of a partisan ad. But this complaint merely highlights the fact that people like Mitchell often carry the water for the president in segments that are labeled straight news when they are nothing more than partisan spin.

Mitchell has come under increasing fire from media critics for conducting a series of hit and run attacks on Mitt Romney, exposed in a series of encounters on MSNBC with GOP surrogate John Sununu in which her partisanship is not debatable. In the clip used by the Obama campaign, Mitchell quotes a liberal group’s claim that Romney’s tax plan will cost $4.8 trillion and will therefore raise taxes on the middle class, a charge that other, more credible analysts, have debunked. This is a point on which even liberal fact checkers have concluded that the Democrats’ pants are on fire, but Mitchell loyally spouted the allegation on the air as if it were objective fact.

The scandal here is not, as NBC seems to be saying, that the Democrats are stealing their material without permission, but that the Democrats were not charged for the air time taken up by Mitchell’s flacking for Obama in the first place.

Mitchell is hardly the only partisan hack masquerading as a fair-minded journalist on one of the networks and perhaps isn’t even the worst (CNN’s Soledad O’Brien certainly gives her a run for her money in this category). But the Obama ad removes even the flimsy veil of false objectivity from her conduct.