The share of Republicans did not change more than one point on average in either poll between then and now. Five polls in both sets breaks down support for Trump and Biden among Democrats, Republicans and independents. The truth was hiding in plain view the entire time; it was the pundit class, not the polls, that failed. Undecided voters tend to break heavily against the incumbent, and in 2016, Clinton was the de facto incumbent seeking to succeed President Barack Obama. In 2016, the bulk of third-party voters were Republicans unhappy with Trump.

Source: Washington Post July 28, 2020 20:14 UTC