By Scott Bauer, AP

MADISON, Wis. (AP) — When the elections clerk in Wisconsin’s heavily Democratic capital city of Madison announced on Sept. 23 that duplicate absentee ballots had mistakenly been sent to around 2,000 voters, it ignited concerns about election integrity from a Republican congressman and others on the right.

Every vote is crucial in Wisconsin, a swing state that President Joe Biden won by just under 21,000 votes in 2020 and that former President Donald Trump won by just under 23,000 votes in 2016. The contest between Trump and Democrat Kamala Harris is close this year as well, creating a hyperintense focus on how elections are run.

Madison is in the heart of liberal Dane County, where more than 75% of voters — more than 260,000 people — voted for Biden in 2020.

Because of Madison’s heavy Democratic tilt, any question about election integrity draws intense scrutiny from Republicans.

Here are some things to know about what happened with the duplicate ballots and the reaction to the error.

How did the public find out about the error?

Madison’s city clerk who runs elections, Maribeth Witzel-Behl, posted a statement online on the night of Sept. 23 explaining that up to 2,000 duplicate absentee ballots had been sent in error. The statement blamed a data processing error and initially said that only voters in one ward were affected. The statement also said that barcodes on the ballots used to track them would ensure that only one ballot is counted.

Are there barcodes on ballots in Wisconsin?

No. There are barcodes on the envelopes that absentee ballots are returned in. Those barcodes make it possible for voters to track the progress of their ballots online. It also allows for election officials to mark off when a voter has cast an absentee ballot, ensuring that they don’t vote again at the polls on Election Day.

Republican raises questions about barcodes on ballots

Tiffany seized on the city’s initial statement that did not differentiate between the ballot and the envelope. In a letter to the city, he asked, “Are unique ballot bar codes linked to individual, identifiable voter profiles?”

The city responded by explaining that barcodes are printed on the ballot envelope, not the ballot. “These types of barcodes are used across the state and the country,” the clerk wrote.

Tiffany on Sept. 27 defended asking that question, saying he was seeking clarity after the clerk’s initial statement did not clearly say the barcodes were on the envelopes, not the ballots.

City spokesperson Dylan Brogan said that he altered the wording of the original statement to specify that the barcode is on ballot envelopes after Tiffany asked the barcode question.

Kevin Kennedy, who was Wisconsin’s top elections official for 33 years and is currently a member of three nonpartisan boards that work in elections, said using the term “ballot” when actually referring to the envelope is commonly done both by election workers and the public.

“If that’s the strength of your argument, focusing on someone misspeaking, that’s not the issue,” Kennedy said. “It probably says more about the motives of the speaker if that’s what they’re going to focus on.”

The city posted its response to Tiffany, which included the barcode explanation, at 6:24 p.m. on Sept. 25. Eighteen minutes later, Tiffany posted a photo of an absentee ballot and quoted from the city’s initial statement that did not differentiate between the ballot and envelope.

Tiffany said, “Although the Madison Clerk’s Office claims, ‘The voting system does not allow a ballot with the same barcode to be submitted,’ my office has proof that there is no barcode on the actual ballots. Here is a picture of the absentee ballots – NO BARCODE.”

That post generated more than 2.4 million views on X as of Sept. 27.

Tiffany said Sept. 27 that he was not falsely suggesting that the clerk was lying about barcodes on ballots. Tiffany said he was trying to point out that it was the clerk, not him, who first said the barcodes were on ballots and not the envelopes.

Also on Sept. 26, X owner Elon Musk, who like Tiffany is a Trump supporter, reposted a message to his nearly 200 million followers that suggested Republicans had discovered that duplicate ballots had been sent.

Who discovered the error and what is being done to fix it?

The error occurred when two data sets were merged, creating a file that listed absentee voters twice, the city spokesperson Brogan said. It was done late last week and discovered on Sept. 23 when the city was contacted by a voter who received two ballots, he said.

None of the duplicate ballots had been returned before the mistake was caught, Brogan said.

The Madison city attorney spoke with the state Republican Party about the incident on Sept. 23 before the city made it public and before Tiffany raised questions about it, Brogan said.

Tiffany’s first public comment about the issue came the day after the city made the public aware of what had happened.

Tiffany calls for an independent investigation

Tiffany, after the city responded to his initial set of questions, on Sept. 26 called for an independent investigation citing “many inconsistencies” including the barcode issue. He also pointed to the city increasing the number of wards affected from one to 10 and the number of duplicate ballots from up to 2,000 to 2,215.

Democrats accuse Tiffany of trying to mislead, sow distrust

Democrats were quick to accuse Tiffany of trying to sow distrust in elections.

“I can’t tell if this is just profound lack of knowledge or the intentional farming of outrage,” Ann Jacobs, the Democratic chair of the Wisconsin Elections Commission, posted on X. “Both, by the way, are bad.”

Democratic U.S. Rep. Gwen Moore also responded to Tiffany’s post about the barcode calling it “misinformation” and telling him to “knock it off.”

Witzel-Behl, the city clerk, told Tiffany in her response letter that “elections are conducted by humans and occasionally human error occurs.”

“When errors occur, we own up to them, correct them as soon as possible, and are transparent about them – precisely as we have done here,” she said.