PORTLAND (AP) — New England’s last remaining Republican congressman ended his legal battle Monday challenging the election of his Democratic opponent under Maine’s new voting system.

U.S. Rep. Bruce Poliquin said in a statement posted on Facebook that he still considers the ranked-choice system confusing. He said he wishes the best for Democrat Rep.-elect Jared Golden, whose swearing-in is set for Jan. 3.

A federal judge in Maine and the 1st Circuit Court of Appeals in Boston both dealt blows to Poliquin’s efforts to have the courts rule the system unconstitutional and either declare him the winner or order another election. Even after the appeals court’s decision, the suit was still alive but with a slim chance of success.

“As such, despite winning the largest number of votes on Election Day, I believe it’s in the best interest of my constituents and all Maine citizens to close this confusing and unfair chapter of voting history by ending any further legal proceedings,” Poliquin said.

This month, U.S. District Judge Lance Walker said that critics can question the wisdom of ranked-choice voting, but that such criticism “falls short of constitutional impropriety.” Poliquin also lost a last-ditch bid to challenge Golden’s swearing-in by asking the courts to halt the certification of election results.

Poliquin claims he should be the winner because he had the most first-place votes on Election Day. But Golden won the race once votes from two trailing independents were reallocated.

Golden said in a statement that he looked forward to getting to work and thanked Poliquin for his service to the state and “the spirited campaign he ran in 2018.”

Maine became the first state to allow voters to rank candidates on the ballots in a congressional race.

Maine’s top state court last year warned that ranked-choice voting conflicts with the state’s constitution, which says the winners of state-level races are whoever gets the most votes, or a “plurality.” So Maine uses ranked-choice voting only in federal elections and state primary races, but not for general elections for governor or the Legislature.

Democratic Gov.-elect Janet Mills has vowed to seek to amend the state constitution so the system can be used in all elections.