I sorted and delivered hundreds of pieces of university mail daily when I was a student employee. We were a large staff but all of us knew a lot such as who was in the John Birch Society, GOP, Dems, Socialist Workers Party, CPUSA and much more. We knew who got Playboy at his campus office and who got thank you mail from political candidates.
The regular US Postal Service carrier for your home and office addresses knows plenty about you, even without post cards to read.
Since around 90% of them are strongly anti-Trump and anti-GOP, they could all decide to dump those nasty ballots in the big mail cannisters or the vacant lot behind Costco. And deliver those Dem ones right on time. Note: remember the Newt Gingrich shutdown over the budget? Placard carrying angry federal workers in photos said "We will remember you at election time." Many were letter carriers or sorters.
A most informative post, my FRiend.
It should be required reading for those in Congress as well as those in the alleged "news" media.
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Thank you for the compliment.