Outgoing Republican Maine Gov. Paul LePage took a swipe on Friday at a Democratic candidate’s victory in a controversial House race, writing “stolen election” next to his signature on the certificate confirming the election result.

LePage certified the victory of Democratic Rep.-elect Jared Golden after Rep. Bruce Poliquin, a two-term Republican congressman, conceded to his opponent on Christmas Eve following a contentious legal challenge.

“I’ve signed off on the [Maine’s 2nd Congressional District] election result as it’s no longer in federal court,” LePage wrote in a tweet, attaching the certificate with the phrase “stolen election” next to his signature.

“Ranked Choice Voting didn’t result in a true majority as promised-simply a plurality measured differently. It didn’t keep big money out of politics & didn’t result in a more civil election,” he added.

The controversy over the race stems from Maine’s “ranked-choice” electoral system, where, if no candidate receives an outright majority of the votes, a second tally is triggered. In that case, the second and even third choices of some voters are added to the total count.

The Republican initially received about 2,000 more votes than the Democrat, short of the outright majority. But Golden managed to surge ahead of Poliquin after second preferences from ballots supporting two other independent candidates were re-allocated.

The incumbent congressman claimed that the system was unconstitutional and requested that the courts either declare him the winner or order another election.

Maine’s top state court last year warned that ranked-choice voting conflicts with the state constitution, which says the winners of state-level races are whoever gets the most votes, or a plurality.

Golden’s upset victory is another setback for Republicans in Congress, who lost the control of the House following the midterm elections.

Maine’s 2nd Congressional District historically leaned Democratic, though its residents voted overwhelmingly for President Trump in the 2016 presidential election.

LePage is being replaced by Democratic state Attorney General Janet Mills, who became the first female governor in the state and the first Democrat to hold the office in over a decade.

The Republican, who served as the state’s governor for eight years, couldn’t run again due to term limits. He previously told reporters he’s retiring from politics and will be moving to Florida due to low taxes.