If Trump seriously stands any chance of winning states like PA, WI, and MI, these voters have to exist in decent sized numbers.
Angry socially moderate/economically left leaning but not far-left white voters who miss the 90s era centrist democratic party and dislike the modern identity-politics driven party obsessed with trayvon martin, etc. esp. courtesy of obama.
Things changed dramatically for the democratic party when Gore lost the EV in 2000.
This is why it's ridiculous that the republican party tried to shove in their own identity politics candidate (rubio) and thought he could win over those disaffected democrats of the new GOP. The whole reason they left the democratic party in the first place was due to identity politics.