HARRISBURG — Philadelphia’s top elections official is warning of electoral chaos in the presidential battleground state if lawmakers there do not remove a provision in Pennsylvania law that, under a days-old court decision, requires counties to throw out mail-in ballots returned without secrecy envelopes.

Lisa Deeley, chairwoman of the three-member board overseeing Philadelphia’s elections, wrote Monday to the state Legislature’s presiding Republicans amid a partisan stalemate over fixing glitches in Pennsylvania’s fledging mail-in voting law.

In the letter, Deeley urged them to back legislation to remove a provision she calls unnecessary and a threat to invalidate more ballots than the margin that decided the state’s 2016 presidential election.

“When you consider that the 2016 Presidential Election in Pennsylvania was decided by just over 44,000 votes, you can see why I am concerned,” Deeley wrote.

Some 30,000 to 40,000 mail-in ballots could arrive without secrecy envelopes in Philadelphia alone in November’s presidential election, Deeley estimated, and the state Supreme Court’s interpretation of current law forces election officials to throw out the so-called “naked ballots.”

Most of the attention revolved around the court’s extension of the deadline for counties to receive mail-in ballots, but “it is the naked ballot ruling that is going to cause electoral chaos,” she wrote.

Statewide, that could mean throwing out more than 100,000 mail-in ballots in the Nov. 3 presidential election, according to some estimates.

Deeley’s letter comes four days after the state Supreme Court rejected the request by the Democratic Party to clarify the law to allow elections officials to count mail-in ballots that arrive without a secrecy envelope.

The ruling was part of a wider decision on contested elements of the state’s election law, and Republicans on Monday said they will appeal one element of the court’s decision — extending by three days the deadline to receive mail-in ballots that were postmarked by 8 p.m. Nov. 3 — to the U.S. Supreme Court.

They also signaled that they are comfortable with the current law on secrecy envelopes.

“We believe this issue is settled for this election,” a spokesman for House Speaker Bryan Cutler, R-Lancaster, said in a statement.

The administration of Gov. Tom Wolf, a Democrat, supported the Democratic Party’s effort in court. But Republicans, including President Donald Trump’s campaign, the state Republican Party and Republican legislative leaders, have argued in court that the law requires mail-in ballots without secrecy envelopes to be invalidated.

One Republican argument was that the secrecy envelope ensures compliance with constitutional guarantees of secrecy in voting.

But Deeley said mail-in ballots are no longer counted at polling places where onlookers might see a voter’s choices on ballot that lacks a secrecy envelope. Rather, mail-in ballots are now processed centrally, by machines, where secrecy envelopes only slow down counting.

“The secrecy envelope exists now only as a means to disenfranchise well intentioned Pennsylvania voters,” Deeley wrote.

Fueled by concerns over the pandemic, more than 3 million voters in Pennsylvania are expected to cast ballots by mail in the Nov. 3 election. That’s more than 10 times as many as voted by mail in the 2016 presidential election, when Trump beat Democrat Hillary Clinton by slightly more than 44,000 votes, or less than 1 percentage point.