Ranked-choice voting
Ranked-choice voting, also known as instant-runoff voting, is a liberal-favored, undemocratic voting system that allows for voters to rank their preferences of candidates on ballots rather than require they choose only one. As with such, the top picks on ballots will be counted for respective candidates initially; if no one gets a majority of the votes cast, the top two proceed, while the votes for the rest of the candidates are one-by-one defaulted to whichever one of the top two that was marked at a higher preference, if signified.
The major issue with ranked-choice voting deals with unfair bias against third-party candidates, which indirectly ensures a two-party system; since voters are given the option to rank their candidates in order of preference, those who rank a third-party candidate as their top choice and either the Democrat or Republican nominee as their second pick, it becomes nearly guaranteed that their vote will go to the latter if no candidate initially garners a majority.
Maine has implemented RCV following the inability of several Democrat candidates to win elections in the state; rather than recruiting stronger candidates to gain certain voters who prefer left-leaning independent candidates, the Democratic Party there instead chose to install a potentially unconstitutional[1] voting system.