Susan Collins just dropped below 50%

[WonderGrunion]

13. It can best be described as an instant runoff election

The system allows voters to rank candidates in order of preference on the ballot, if they choose to do so. Voters can select a first choice, second choice, third choice, fourth choice, etc. They are not, however, required to rank candidates by preference, and may opt instead to only select a single candidate, who would be their first and only choice.

If one of the four Senate candidates receives a majority of the vote -- or 50% plus one -- on Election Night that candidate will win the race outright without ranked-choice tabulation taking effect.

But, if that does not happen, then the lowest-ranked candidate of the four will be eliminated. If that candidate's supporters ranked other preferences, their votes will then be assigned to their second-ranked choice. That process will repeat until only two candidates remain with the winner determined in the final round.