It WAS tested in court, and rank choice voting was found to violate the Maine Constitutional....which mentions a plurality of votes...but not the U.S. Constitution, which does not mention a plurality, according to the judge who heard the case earlier in the year.
Therefore, rank choice was not used for governor, or any of the races for the Maine House or the Maine Senate, but was used in the U.S. Senate race and the two U.S. House races.
In the U.S. Senate race, with Angus King running for re-election....he received more than 50.1% of the vote and the 1st congressional district race....with Shelley Pingree running for re-election....she also received more than 50.1% of the vote so rank choice voting did not kick in.
Federal courts are prohibited from giving advisory opinions, and there’s a very strict “case or controversy” requirement. I assume that the Maine constitution permits challenges to election laws before they actually affect anyone, but such challenge in federal court under the U.S. Constitution needed to wait for someone to have standing to sue, which is why Poliquin had to wait until now.