On Tuesday, Maine Republican Rep. Bruce Poliquin filed a federal lawsuit to overturn what is expected to be a re-election defeat thanks to Maine’s new instant-runoff voting law (IRV; sometimes called ranked-choice voting). However, Poliquin's argument is beyond weak, and if he ultimately succeeds, it would make a mockery of the rule of law in much the same way that Bush v. Gore did.
After 95 percent of the initial votes have been counted, Poliquin holds a slim 46.2-45.5 plurality over Democrat Jared Golden, but because Maine voters passed a 2016 ballot initiative to enact IRV, it takes a majority to prevail. However, instead of holding a separate runoff, voters got to rank their preferences, and since nobody took a majority in the first round, the last-place finisher gets eliminated and sees their votes redistributed to each of their voters' subsequent preferences. That process repeats until one candidate wins a majority, and the Bangor Daily News conducted an exit poll that found voters who backed the two independent candidates overwhelmingly favored Golden in subsequent rounds.
Ever since voters passed this law, Maine Republicans and a small minority of Democratic legislators tried repeatedly to get rid of it, but voters vetoed the legislature’s attempt to repeal the law in a 2018 referendum. While Maine’s Supreme Court indicated last year in a non-binding opinion the law was invalidated for state-level general elections, they didn’t say it was invalid for primaries or federal general elections, and the secretary of state implemented it for both of those elections.
Consequently, Poliquin is resorting to federal litigation by arguing that Article 1, Section 2 of the Constitution requires only pluralities be sufficient for election to the House. However, that section literally says nothing related to whether candidates must obtain a plurality or majority—or even any election method at all—and the cases the congressman cited come nowhere close to supporting his argument that the Constitution requires only pluralities.
Furthermore, Poliquin had ample time to file this lawsuit well before anybody actually voted yet didn’t, and filing it after votes were already all cast would violate other long-standing precedents. Election law experts have derided this lawsuit as "beyond frivolous," and there’s a good chance the courts will resoundingly reject it.