The effects of alternative electoral systems such as Ranked Choice Voting on third-party and independent representation in the United States is a major topic of FairVote's research. Although there are examples from abroad (for instance, the multi-winner use of RCV in the Australian Senate is thought to slightly increase the representation of minor parties (Bowler and Grofman, 2000), the unique two-party, candidate-centered system of the US makes extrapolating the overseas experience difficult.
While RCV might not increase the election of third party or independent candidates in the US, as candidates must clear a threshold of the total vote (a threshold that decreases the more candidates that are being elected), RCV allows supporters of third parties and minor candidates to sincerely rank their preferred candidate first without feeling like their votes are wasted (Lewyn, Michael (2012)). RCV also minimizes the spoiler effect of third party votes. Under RCV, third party and independent supporters can rank their most preferred party or candidate first. If their candidate is eliminated, their votes immediately transfer to their second choice preference. Third parties supporters are thus free to elect their favorite candidate with minimal chance that that support will spoil the election outcome (Bartholdi III and Orlin,1991, Bowler and Grofman, 2000).
Along with preventing spoilers, RCV may also help keep the major parties more accountable to the electorate. Candidates are incentivized to court a broader range of voters than they normally would, including asking for second and third choice rankings from minor-party supporters.
In multi-winner RCV, it also becomes possible for Democrats or Republicans that live in a district with the opposite majority to gain representation. As long as the Democrat or Republican population is equal to or greater than the threshold to win, people can gain representation where they currently feel left out.