Al Diamon’s description about ranked-choice voting (“Politics & Other Mistakes: Ranked-choice snake oil”) is right on the mark.
RCV has been proposed as a voting methodology that will produce a “majority” candidate, improve the tenor of the debate, and improve the opportunity for political minority candidates. Unfortunately, these “facts” may not be true, as was shown in the 2011 Portland mayoral election, when Mayor Michael Brennan was elected with a plurality – approximately 800 votes below a majority of all the ballots cast.
As for improving the tenor of the debate, the candidates may become even more partisan as they know that the supporters of their opponent of a similar ideology will still vote for them and would never vote for a candidate from the other ideology. The goal of RCV is to eliminate the “spoiler” candidate and protect the major-party candidate. Generally, this will be a Democrat, as most independents and the minor-party candidates, e.g. Green Party, lean to the left. But voting methodologies are no respecter of political identity.
In the recent presidential election, if under RCV – and assuming the Libertarians would have voted for Trump as second choice, the Green Party would have voted for Clinton as second choice, and the Independents voted for neither – Trump would have won Maine together with two more Electoral College votes.
Finally does a “majority” candidate who is elected by a loose coalition of splinter groups, each with their own priorities, have the same mandate as a candidate elected with a strong plurality?