A federal judge on Monday ordered the North Carolina Board of Elections to certify the results of a contentious State Supreme Court race, rejecting efforts from the Republican challenger to throw out thousands of votes.

The ruling is the most significant legal victory yet for the Democratic incumbent, Justice Allison Riggs, as the case has ping-ponged through state and federal courts and tested the boundaries of post-election litigation.

Two recounts confirmed that she won in November by 734 votes. But the Republican candidate, Judge Jefferson Griffin, has for months sought to reverse his loss by calling into question the eligibility of thousands of voters.

On Monday, the federal judge, Richard E. Myers II of the U.S. District Court for the Eastern District of North Carolina, ordered that all the challenged ballots should be counted. Not doing so would violate the constitutional due process rights of those voters, he said.

“You establish the rules before the game,” Judge Myers, a Trump appointee, wrote in his 68-page ruling. “You don’t change them after the game is done.”

But he gave Judge Griffin, who sits on the North Carolina Court of Appeals, seven days to appeal. That means that the ruling may not be the end of the case.