Colorado's another example of why there won't necessarily be a "blue shift" in late-counted ballots (and could even be a red shift). Dems lead by 13 points in mail ballots returned so far. But the mail ballots that *haven't* been returned yet are +3 GOP.

https://electproject.github.io/Early-Vote-2020G/CO.html

Mail is the only way to vote in Colorado and every registered voter gets a ballot, so it's not like these Republicans are sitting around waiting to vote in person. They're just waiting longer to send in their ballots.

Or maybe some of them won't vote at all, in which case polls might be underestimating the D turnout advantage and Republicans could get some very bad results.