In elections, there are winners and losers, and there are lawsuit filers, who are usually also the losers.
In the 2018 District 2 election in Maine, this is precisely the case, and the case of Representative Bruce Poliquin just doesn't look good. After the ranked-choice voting, that Maine voters approved a couple years ago, helped Poliquin's opponent Jared Golden win the race, Poliquin filed a lawsuit challenging ranked-choice voting as unconstitutional.
Is Ranked-Choice Constitutional?
It would seem that there really isn't an issue, generally, with ranked-choice voting systems, as the preliminary injunctions requested by Poliquin have been denied.
However, from Poliquin's perspective, the ranked-choice voting burned him pretty badly as he was ahead of Golden until the second-place votes were accounted for, which pushed Golden ahead by more than 1%. Poliquin has requested a recount, and has expressed his belief that he should be declared the winner because he won the first-choice phase, or runoff phase.
As reported by NPR, it's not expected for Poliquin's lawsuit to be successful, particularly as he waited until after the election to file and knew all along that ranked choice voting would be used. However, his attorney commented that filing before the election would have been too early. But that seems to run contrary to several of their challenges which seem to assert various forms of voter disenfranchisement due to ranked-choice voting making some people's second votes matter, while other peoples' second votes don't.
Meanwhile, the recount Poliquin requested is underway, and unfortunately for him, if the recount doesn't result in changing the result, he'll be on the hook for the costs.