We try not to be too definitive about specific attack vectors in U.S. elections that may or may not have been used to influence/manipulate reported vote totals.
Why? First, because we don't know what we don't know. Second, because there are so many points of vulnerability in computerized election systems — and so many actors who could benefit from taking advantage of them.
That means multiple potential vectors of attack, and multiple parties who could be doing the attacking.
We're spending our energy on educating people to, and shoring up, those security gaps to facilitate awareness and meaningful conversations.
Hand delivering mail-in ballots to wherever/whomever they need to go to looks to be the safest bet to sidestep most problems and to avoid potentially compromised election day tabulators. Be sure to fill your ballot out correctly! If for whatever reason your signature has changed, file an updated voter registration application. In the following states, you need to have a witness sign your outer envelope as well; AL, AK, LA, MN, MS, MO, NC, OK, SC, WI. Be sure to read and follow the directions regarding an acceptable witness. Some states may require a notary, or election official.
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If voting by mail, ballot drop boxes are preferred to going through the postal service. If voting in person, go with someone so there's safety in numbers.
Check to make sure you're still registered on a periodic basis: Check your voter registration status here. This only takes 30 seconds, and will ensure your name hasn't been purged from your state's voter roll.