By Noel Sheppard | December 5, 2008 | 10:42 AM EST

If "Hardball" host Chris Matthews is indeed going to challenge Arlen Specter for his senate seat in 2010, he must resign his position with MSNBC.

So say a growing chorus of observers from both sides of the aisle.

As reported by Politico's Michael Calderone Thursday:

By Matthew Balan | September 3, 2008 | 7:24 PM EDT

Less than two hours after Peggy Noonan and former McCain advisor Mike Murphy appeared on MSNBC Wednesday afternoon, a YouTube video appeared of their candid exchange in which they dismissed Sarah Palin’s viability as a VP pick. The speed at which the video appeared indicated that it almost certainly originated from someone inside MSNBC, another favor for the Democrats this election year.

Joshua Micah Marshall’s blog Talking Points Memo and the blog of Michael Calderone of the Politico broke news of Noonan and Murphy’s comments. The exchange started as MSNBC Chuck Todd previewed what was coming up next on the program before a commercial break 20 minutes into the 2 pm Eastern hour, as Noonan and Murphy began a discussion off-camera, picked up by a hot mike. Todd then joined the discussion once the commercial break began. None of their discussion actually made it on the air for this reason.