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Last summer, Sen. Bill Nelson (D-Fla.) drew skepticism and ridicule from the media and Republicans when he claimed that Russian hackers had gained access to local election systems in his state. Eight months later, special counsel Robert Mueller’s report appears to back him up.

In November 2016, the Mueller report states, Russia’s military intelligence agency, the GRU, sent emails to more than 120 accounts used by Florida county officials involved in election administration. The emails appeared to come from a voting system software vendor and contained an attached Microsoft Word document that, when opened, unleashed malicious software that would permit the GRU to access the infected computer—a kind of attack known as spear-phishing. This much was already known. But the report, which details Russian interference in the election that includes the Kremlin’s attempt to penetrate state election systems, adds one more tidbit: “We understand the FBI believes that this operation enabled the GRU to gain access to the network of at least one Florida county government.” If true, that would appear to support Nelson’s claim, which Republicans mocked and used against him in his unsuccessful reelection bid in November.

In August 2018, Nelson warned that Russians had penetrated some county governments in his state. “They have already penetrated certain counties in the state and they now have free rein to move about,” Nelson told the Tampa Bay Times. “We were requested by the chairman and vice chairman of the Intelligence Committee to let supervisors of election in Florida know that the Russians are in their records.”

The response to Nelson, who said the evidence for his claim was classified, was sweeping and negative. Republicans and the media alike painted his comments as dangerous make-believe.

Florida’s Republican secretary of state categorically denied it. Gov. Rick Scott, the Republican who would go on to defeat Nelson in the Senate race, attributed his comments to “confusion.” Soon, Republicans were using the comments to attack Nelson, hinting that he had made up the threat. The media was no kinder to Nelson. Reporters on Twitter were dismissive. MSNBC host Chuck Todd dubbed Nelson’s comment an “unforced error” in his campaign. The Washington Post conducted a fact-check of his comments and awarded Nelson four Pinocchios—the number reserved for the most egregious lies—even though it had no access to the classified information Nelson said backed up his assertion. The Department of Homeland Security said, cryptically, that it was unaware of “any new compromises by Russian actors.”

Nelson faced all this backlash even though it was already public knowledge (through a leak of a top-secret National Security Administration document) that Russia had targeted local election officials in Florida in 2016, as the Mueller report reiterates. And if they were successful then, it was possible they were still lurking in the system ahead of the midterm elections. As J. Alex Halderman, a University of Michigan computer scientist and a leading expert on voting security, told Mother Jones last spring, “If Russia is planning to attack the 2018 election, they right now already have found their ways into the computer systems they’re going to use.” Indeed, 10 days after Nelson’s comments, NBC News reported that sources confirmed a classified basis for Nelson’s comments, stemming from ongoing threats from the 2016 attack.

If the Mueller report is correct, Russians may well have penetrated Florida counties and maintained that access in 2018—and most of the political world mocked the person who warned about it.

Listen to our DC bureau chief David Corn discuss Mueller’s findings on this special breaking news edition of the Mother Jones Podcast: