On Monday, Facebook CEO Mark Zuckerberg announced a major milestone for what he called “the largest voting information campaign in US history.” Launched in August with the goal of registering 4 million Americans to vote, Facebook claimed the effort garnered an estimated 4.4 million registrations across the company’s social media platforms, based on conversion rates the company calculated from “a few states it had partnered with.”

“Voting is voice,” Zuckerberg wrote in a post to the company’s internal message board, specifically thanking Facebook’s civic engagement and civic integrity teams. What he didn’t mention, however, was the resistance the voting information campaign faced from Republican-led secretaries of state.

In September, Facebook received a strongly worded letter signed by the secretaries of state of Alabama, Idaho, Kentucky, Louisiana, Mississippi, and West Virginia, asking the company to discontinue its Voting Information Center. It argued election officials alone are “legally and morally responsible to our citizens” and said Facebook has “no such accountability.”

“While such goals may be laudable on their face, the reality is that the administration of elections is best left to the states,” read the letter, which was addressed to Zuckerberg. “The Voting Information Center is redundant and duplicative of what we, as chief election officials, have been doing for decades.”

The six Republican secretaries of state warned that the voting information center could foster “misinformation and confusion.”

The letter, which was obtained through a Freedom of Information Act request by Common Cause, a nonprofit government watchdog group, reveals the partisan hostility faced by the $800 billion company as it sought to provide people with what Zuckerberg previously called “the single most powerful expression of democracy.” Over the past year, Facebook has faced fierce criticism from both political parties, with Democrats arguing the social network hasn’t done enough to limit the spread of political misinformation and hate, while Republicans have argued — largely without evidence — that they’re victims of anti-conservative bias.

“We think every eligible person should have the information they need to register and vote,” Facebook spokesperson Kevin McAlister said in a statement. He declined to comment directly on the letter.

Jesse Littlewood, vice president for campaigns at Common Cause, called the effort by the secretaries of state a “remarkable” attempt to “strong-arm Facebook.”

“It’s troubling to see those overseeing elections try to stop what appears to be a successful project to register voters,” he said.

The Sept. 2 letter sent to Zuckerberg and two members of Facebook’s government and policy teams was not the first time Republicans complained about the company’s Voting Information Center, a website that included information about voter registration and how to cast a ballot by mail. Earlier this summer, following Facebook’s announcement of the effort, Trump campaign officials alleged that the company would use ad targeting to help register people that would oppose the president.

“With knowledge of every user’s political ideology, Facebook is officially in the business of political advocacy and their efforts to silence conservative voices should be seen as nothing less than an attempt to ultimately benefit Biden and the Democrat Party,” Samantha Zager, a spokesperson for the Trump campaign, told Bloomberg News in July.

Facebook denied that any ad targeting would be used in its voter registration drive.

In their letter, the six Republican secretaries of state said some of the information Facebook planned to use in its Voter Information Center was incorrect.

“Accordingly, the undersigned respectfully request that Facebook discontinue its Voter Information Center project in our respective states, and refrain from publishing or promoting election information retrieved from or created by any source except state/territory chief election officials,” they wrote.

The letter came after Facebook reached out to secretaries of state across the country asking them for information that it would include on the Voting Information Center ahead of its Aug. 13 launch. In correspondence obtained by Common Cause, Donald Kersey, general counsel for the office of West Virginia Secretary of State, said in an Aug. 6 email that he had “strong concerns” about aspects of a mock informational page for voting in the state that had been sent to him by Rachel Holland, a Facebook government outreach employee.

The pair went back and forth via email, before Kersey wrote on Aug. 14, “Please consider this writing exclusive notification that West Virginia does not wish to make the tool available at the local level at this time.”

Facebook moved forward with the voting information center, leading the six secretaries of state to send their letter in early September. Two days later, Kersey followed up with another email.

“On behalf of Secretary Warner, West Virginia’s chief election official, Facebook has been asked to cease its VIC project in our state for the concerns raised in several previous letters,” he wrote. As of Tuesday, Facebook’s voter information center was still operational for addresses in West Virginia, according to a test by BuzzFeed News.

In an email to BuzzFeed News, Kersey said that voter registration drives “have been conducted by countless third parties for decades” and that the purposes of his correspondence was meant to prevent “pushing unofficial election information to voters.”

Common Cause, which sought correspondence between Facebook and all 50 secretaries of state, also obtained correspondence between the company and a state election director in North Dakota, who said that the social network’s initiative was “not helping.”

“We don’t have time to keep fact-checking Facebook, especially when finding that errors and misinformation continue,” state election director Brian Newby wrote to a Facebook official on Sep. 28. He noted that “technically there is no deadline to request a ballot,” though Facebook’s site noted potential voters in the state had until Nov. 2, the date that a mail-in ballot has to be returned or postmarked in the state.

While North Dakota’s secretary of state was not a part of the letter sent to Zuckerberg, Newby told BuzzFeed News in an email that third-party sites like Facebook “risk disenfranchising voters with incorrect information.” He added that he didn’t doubt the motivations of Facebook in North Dakota, which unlike other states, does not register voters.

Not all signatories of the Sep. 2 letter continued to believe Facebook was a detriment to their efforts. Earlier this month, Alabama Secretary of State John Merrill sent a press release commending social media platforms for encouraging voter registration and participation.

“I am grateful to social media platforms including Facebook, Google, Instagram, Snapchat, Twitter, and others who are amplifying the message promoted by election officials across the country during this historic election year,” he said in an Oct. 8 statement. A Facebook spokesperson also sent the release to reporters to make them aware.

Grace Newcombe, the press secretary for Alabama’s secretary of state, told BuzzFeed News that Merrill’s office was pleased with changes made by Facebook after the initial letter was sent.

“Facebook has made a concerted effort to direct voters directly to our website AlabamaVotes.gov as opposed to a third-party site,” she said, adding that the effort helps Alabama reach “a record-breaking 3,707,772 registered voters.”

The estimated 4.4 million people that Facebook said it registered more than doubled the number of people the company claimed to have registered for in the 2016 presidential election and 2018 midterms.

There’s a lot to be critical of Facebook for, said Common Cause’s Littlewood, noting that the company has a long way in terms of moderating organic electoral content and fixing algorithmic amplification of groups that violate its terms of service. On Tuesday, the company faced heat after incorrectly preventing candidate ads from running seven days before the Nov. 3 vote.

“This voter information center was supportive of democracy,” Littlewood said. “If those numbers are true and Facebook did register a large number of voters, it will be great to see some information about how many of those voters end up casting a ballot.”