PHOENIX — What former president Donald Trump seems to think is his best hope to unravel the 2020 election looks a lot like an outsize board game — a game with few apparent rules and no clear endpoint. On a recent day on the floor of a sports arena with a roof shaped like a Pringle, there were four teams of ballot-counters clad in cartoonish colors: banana yellow, Gumby green, Cookie Monster blue, and Elmo red. They were clustered in groups of three around big round tables, each outfitted with a lazy Susan that matched their T-shirts and whirled ballots...