I see this come up a lot in discussions about voting in America. Postal votes disproportionately go to Democrats, hence the Democrats want to expand postal voting while Republicans want to restrict it (and insist there is totally a bunch of fraud going on).
I’ve googled with a few search engines and haven’t found a convincing reason. Lots of evidence that the skew is real, but no explanation as to why. Indeed, if one just looks at demographics, one would expect postal voting to benefit Republicans by facilitating votes from people in the countryside who live far away from voting centers.
So what actually gives?
You’ve gotten some good answers already so I’m going to comment on something unrelated, mostly because I’ve had a couple glasses of wine and for some reason found this hysterical.
I’m old enough to remember search before Google, the rise of Google and the verbification of Google’s name to become a term to meaning to search with Google. To see it now used in this way is deeply funny to me for some reason. Incredible to see how language evolves over time.
I’m doing my part to genericise Google®'s trademark.