MSNBC has a penchant for repeatedly hosting wingnuts who have been previously exposed as frauds -- exposed as frauds by MSNBC. The list begins with guys like Chuck Grassley and continues on with various talk radio wingnuts and various other "strategists."
And then there's Mike Pence who was debunked on healthcare by Andrea Mitchell this week, but then turned up on MSNBC again the next day spreading the same crap -- only to be debunked again by Carlos Watson.
Now MSNBC might argue that exposing the big lie is the whole point, but perception doesn't really work like that. Mike Pence never admits to lying about taxes, so it's a judgment call by the viewer as to whether or not he's full of shit. Meanwhile, Pence has been allowed an open forum to inject his disingenuous wingnut/Luntz/Castellanos talking points into the discourse even though he was debunked the day before.
So the serious question regarding MSNBC's credibility as a news outfit is this: What level of insanity will get a wingnut banned from MSNBC? How far off the rails does a remark or lie have to be in order to not be invited back?