A federal judge has pushed away a legal challenge to Maine's new ranked-choice voting system.

In the November midterms, incumbent Republican Rep. Bruce Poliquin won the first round of votes against Democratic challenger Jared Golden. But he did not get more than 50 percent of the votes, since there were two other independent candidates in the race. Under Maine's new election rules, put into place by the voters, a candidate for Congress must get a majority of the votes, not just a plurality.

To resolve this problem, Maine voters are asked to rank the candidates in order of preference. If no candidate gets a majority vote, the candidate who received the least votes is eliminated from the race. The ballots are tallied again, but for those who voted for the eliminated candidate, their second choice is counted as their vote instead. And so it goes until a candidate gets the majority vote. It's essentially an instant runoff system.

In Maine, more of those independent voters selected Golden than Poliquin as their second choice, and that pushed Golden ahead to narrowly win with 50.6 percent of the vote. Poliquin sued to try to stop the vote count, challenging the constitutionality of ranked-choice voting.

U.S. District Court Judge Lance Walker, appointed by President Donald Trump, roundly rejected Poliquin's suit in a 30-page ruling. Poliquin and the other plaintiffs—a couple of Poliquin voters—had argued that Article 1, Section 2 of the U.S. Constitution calls for plurality voting. But it does not. The text says members of the House of Representatives will be elected by popular vote, but it doesn't state whether the winner should be determined by a plurality or majority.

Walker ruled that this is intentional. States have historically been free to decide the threshold for victory, and—as Walker noted—some have separate run-off elections to determine a majority vote winner.

Walker also rejected an argument by the Poliquin-voting plaintiffs that the system violated the Equal Protection Clause of the 14th Amendment by not treating their votes with the same "weight" as others. The plaintiffs only voted for Poliquin and declined to rank the other candidates, which is permitted. They argued that this meant that their votes had less "weight" then those who ranked their candidates. This made little sense and the judge rejected it. They chose not to rank the other candidates, but the option was presented. And during each round, each person's vote counted only once.

Now, there is an issue where a person's ballot is "exhausted" if he or she voted only for a candidate who is eliminated from subsequent rounfs. In that case, that person's vote is arguably wasted. But that's no different from what happens in conventional election system—and it isn't what happened to Poliquin voters anyway. Their votes were equally counted in the second round of votes.

So it looks like Maine's ranked-choice voting system is here to stay. This shouldn't be a surprise, as a handful of cities have already been using such systems. But Maine is the first to use it for broader elections.

Maine voters actually wanted to use it for more than just congressional elections. They authorized its use for statewide races and state lawmaker races too. But Maine's constitution, unlike the United States Constitution, specifically orders that election winners for those races be determined by a plurality vote. In order to comply with the voter-approved ballot initiative, lawmakers need to amend the state's Constitution. Right now state Republicans have been resistant. We'll see if this ruling gets them to accept the public's will.

Read Walker's order here.