It would depend on the candidate, but against Hillary or Bernie I think he wins again. I think the Dems became too liberal and alienated a large portion of moderates.
I agree that the Dems moved too far to the left but the Republicans have also moved far left so I think there's a lot of alienation in both parties. I think a Republican will step up to challenge Trump and if the Dems don't start finding someone new who moves them back further towards a moderate position, the Republicans can win again.
However, I don't think Trump can win again no matter who the Dems put out. If Trump runs, there is so much anger towards him that it will mobilize far more people to vote to avoid 4 more years of this embarrassment.
I agree that the Dems moved too far to the left but the Republicans have also moved far left so I think there's a lot of alienation in both parties. I think a Republican will step up to challenge Trump and if the Dems don't start finding someone new who moves them back further towards a moderate position, the Republicans can win again.
However, I don't think Trump can win again no matter who the Dems put out. If Trump runs, there is so much anger towards him that it will mobilize far more people to vote to avoid 4 more years of this embarrassment.