Open primaries, allowing Democrats to mess it up for Republicans. See detailed explanation here https://www.deseret.com/2022/9/1/23332574/how-did-sarah-palin-lose-alaska-special-election
That makes no sense. If...like you claim...Palin voters were tricked into voting for someone else due to the format of the primary, then they surely would make Palin their second choice right? The Begich voters were not Republicans, the Dems had better turnout!