There has been much discussion about whether votes in this next election will be counted securely.
Every state has rules about what poll observers can do at the polls and how votes can be challenged. Here are the rules for your state:
South Dakota At least one poll watcher for each political party, one poll watcher for each independent candidate, one poll watcher for each slate of presidential electors, and one poll watcher for each side of any ballot issue to be voted on may be present at each polling place for general elections. (Administrative Rule 5:02:12:02)
Any person, except a candidate who is on the ballot being voted on at that polling place, may be present at any polling place for the purpose of observing the voting process. (S.D. Codified Laws § 12-18-9)
The person's right to vote at that poll and election may be challenged only as to the person's identity as the person registered whom the person claims to be or on grounds that within fifteen days preceding the election the person has been convicted of a felony or declared by proper authority to be mentally incompetent. (S.D. Codified Laws § 12-18-10)