Our reliance on the polls last time proved to be a massive disappointment and presented inaccuracies. Michigan definitely won't be voting for another TPP globalist.
Polls were fairly accurate last time given the margin of error. Combine that with the fact that they have improved since then (evidenced by their much greater success in 2018, especially in the House elections/popular vote) and the fact that many of the final polls took place right as the Comey effect was being felt, and Trump’s approval rating has remained consistently dismal... There is certainly no rational reason to discount them.
Of course, I would never expect rationality from a self-proclaimed Democrat whose signature suggests he supports two non-Democratic populist candidates who couldn’t be more different ideologically and who rants about “TPP globalists” in 2019. Rationality is indeed the very last thing I would expect from such a person.
If anything, the Democratic Party has been nothing but irrational. Why support establishment Dems when the Progressives can win?