Alaska’s new system of electing candidates starts with a nonpartisan primary in which the top four finishers advance to the general election and voters only make one pick. But in the general election, voters rank their choices on the ballot. If no candidate wins a majority of first-choice votes, the lowest-performing candidate is eliminated and their backup votes are reallocated among the remaining contenders. The process continues until there is a winner.

Peltola led after first-choice votes were counted in the special election. Palin, in second, made up ground but still didn’t overtake Peltola after the backup choices of Begich, who finished third, were factored in. (The fourth finalist ended his campaign before the election, leaving just three on the ballot.) About half of Begich’s first choice voters ranked Palin second. But nearly 30 percent chose Peltola second, while 21 percent ranked neither Peltola nor Palin — an outcome referred to as “ballot exhaustion.”