Since Hillary Clinton's what happened is coming out in 3 weeks, I think it is important to look at some current “blue wall” polling numbers. Lets just say I hope Clinton does not try to artfully pass the blame to Obama or for that matter Sanders. We shall see.
Some favorability ratings from voters in Michigan: August 2017
Trump -25
GOP -24
Snyder -11
Kid Rock +2
Dems 0
Stabenow +7
Sanders +26
Obama +32
(NBC/Marist)
Some favorability ratings from voters in Wisconsin: August 2017
Trump -29
GOP -24
Walker -13
Dems -10
Baldwin +5
Bernie +20
Obama +26
(NBC/Marist)
Some favorability ratings from voters in Pennsylvania: August 2017
GOP -30
Trump -22
Dems -5
Wolf +10
Casey +12
Bernie +15
Obama +28
(NBC/Marist)
I think you can see a clear pattern in these Midwest and RustBelt “Trump States”.