The predictive models that actually suggested Trump would win 2016 are not based on the actual candidate but based on party / whether the current US situation suggests it will be a "change" election. The models would have predicted any Republican to win 2016. Those models incorporate scandal, and that is a negative factor. Impeachment, of course, being a pretty major player in the way of scandal. Has Trump changed the rules of how the public votes? I don't actually think so. The models which don't include polls and subjective ideas predicted Trump would win. I feel highly likely they'll be accurate in 2020. The most compelling predictor in Trump's favor is the economy, although that obviously can change over the next 11 months. Without impeachment and economy holding stable, I believe Trump would win. Who the candidates end up being is probably not all that important unless a significant third party candidate emerges or the Dem candidate has to contend with scandal themselves. Even though it's a manufactured one, the noise Republicans are raising against Biden might have an influence. Principally, we have to realize that even the most uninformed posters on this board are far more attentive to actual political happenings than a typical American. Plenty of people are going to hear Trump was impeached and think negatively of him without any awareness of arguments for or against.