I think this is being read into a little more than it should. I don't think you can count out the particular bad timing of this poll given Murkowski's past month. I think when all is said and done Murkowski has more cards up her sleeve and more leverage in being re-elected than she doesn't. I think this is more of a reflection of the confluence of her position in GOP + how bad GOP brand is now/huge Dem advantage in the generic ballot. At the end of the day, I think Alaskan Independents are more inclined to support her in two years than what the poll reflects now
She voted to.acquit Trump and say that to Dan Sullivan whom is in a tight race with Gross.
Rs think that this is 2016, 1992, 96, 2006, 08, 12 and 2018 prove Ds can win 50 states not just 278
She also voted against Kavanaugh. Not sure what your last point means