As MSNBC continues to Lean Forward to ratings success — for the first time ever during a political convention, the network beat CNN in total viewers Wednesday night in every hour from 7pm-1am — the pretense of being informed without bias from NBC News, is being tested.

The NYT’s Alessandra Stanley analyzes the network during coverage of the RNC.

MSNBC offers counterprogramming, not coverage. All that arch sarcasm and partisan brio may rev up the cable channel’s fans, but it constrains — and stains — NBC News, its corporate sibling, which is still the country’s No. 1 source in the evening…

NBC’s chief anchor, Brian Williams, has conspicuously avoided the most fractious MSNBC discussion panels. Those anchors who do make dutiful appearances, like David Gregory and Tom Brokaw, are badly needed but don’t stay long or join the fray — like piano players in a brothel, they don’t go upstairs.