Alabama Secretary of State John Merril says Republicans cannot swap candidates after allegations that GOP nominee Roy Moore romantically pursued teenagers as young as 14 while he was in his 30s.

Moore, a prominent social conservative, denies the allegations, questioning why they did not emerge earlier in his decades of public life. But still, many Republicans say he should stand down if the claims are true.

Merril told the Washington Examiner that Republicans are out of luck if they want to change candidates ahead of the Dec. 12 election.

“You can’t substitute a candidate after the ballot has been certified,” he said. “It would be against the Code of Alabama.”

The ballot was certified on Oct. 18, Merril said, and “ballots have already been printed and a lot of people have already voted.”

Republicans dissatisfied with Moore are free to launch a vote-in campaign, Merril said.

Alabama has a “sore loser" law, but Merril said that law only applies to names printed on the ballot, meaning appointed Sen. Luther Strange, who Moore defeated in a September primary, can seek election through that route.

“Sen. Strange could still be a write-in candidate, but he cannot be a candidate whose name appears printed on the ballot, that would be a violation of the sore loser law,” Merril said. A spokesman for Strange's campaign did not immediately respond to a request for comment on his plans.

“If you are a candidate who gets the most votes, then you’re going to win,” Merril added. “If more people wrote an individual’s name in through a write-in campaign someone might initiate, that person would become the U.S. senator.”

Sometimes write-in campaigns work. Alaska Sen. Lisa Murkowski, for example, won re-election through a write-in campaign in 2010, with 39.5 percent, after being defeated in the Republican primary.

Contrary to some initial reporting, Merril said the Alabama Republican Party cannot withdraw the nomination of Moore, thereby invalidating all votes that are cast for him.

"The Republican Party can't do anything about this, they've already certified him as the nominee," Merril said. "He is the nominee of the Republican Party and he will be the nominee of the Republican Party."

Merril, a Republican, said he still plans to vote for Moore, though he will closely watch the fallout from the Washington Post’s bombshell Thursday report, which quoted a woman describing sexual touching when she was 14 and Moore was 32. Three other women said Moore pursued them when they were 16 to 18 years old and he was in his 30s between 1979 and 1982.

“Judge Moore’s statement says he is not guilty and I have every reason right now to believe him,” Merril said, questioning why the allegations did not emerge earlier against Moore, who was deposed as chief justice of Alabama’s supreme court in 2003 for defying federal court orders to remove a 10 Commandments sculpture. Moore was re-elected to the position and suspended last year after telling state officials to defy the U.S. Supreme Court’s national legalization of same-sex marriage.

Even before the latest allegations, Moore was in an unexpectedly close race with Democratic candidate Doug Jones, a low-profile former U.S. attorney.

Jones is the only other candidate whose name is printed on the ballot.

Libertarian candidate Ron Bishop is running as a write-in candidate and said he hopes the allegations against Moore will prompt voters to consider his bid.

“A Democrat in Alabama is very hard to get elected,” Bishop said.

Still, Bishop has no illusions that he will be the next senator, who will permanently replace Attorney General Jeff Sessions. Strange, his appointed successor, was accused of possible impropriety for accepting the job from a governor his attorney general’s office was investigating.

“Realistically, we would love to pull 6 to 7 percent,” Bishop said.