Early voters
Bush was probably referring to absentee voters, who from what I’ve heard, the majority are Republicans and this could be a year when all the votes will be needed to determine the finale outcome.
Most political races can be determined without counting the absentee votes and or before all the polling stations report their total count.
This yer could be different and with the news of the major media exit poll results being quarantined from other news outlets it could be interesting as well.
Remember how the exit polls didn’t work in the media’s favor last time?