(CNN) David Sirota, a journalist and social media provocateur, was formally announced Tuesday as a new senior adviser and speechwriter for the Bernie Sanders campaign.
Sirota, who is known for both his reporting and combative Twitter presence, had been informally advising the campaign on a trial basis since the day after Sanders formally launched his 2020 bid for the presidency last month. But shortly before his hiring was announced, Sirota began erasing old tweets, many of which ran contrary to Sanders' call last month for supporters and surrogates to adopt a more friendly tone in their public exchanges with political rivals.
According to campaign manager Faiz Shakir, Sirota began the trial arrangement, in which he would assist Sanders with speechwriting, on Feb. 20, a day after Sanders made his candidacy official. Sirota left his post with the Capital and Main website on Feb. 14, Shakir said. He then signed a formal letter to become the campaign speechwriter on March 11. The trial period was to see how Sanders, who traditionally prefers to handwrite his own speeches on yellow-lined paper, would work with a speechwriter.
Sirota did not respond to CNN's request for comment on his new role with the Sanders campaign.
Sirota's last byline for Capital and Main was on Feb. 6, an interview with Washington Gov. Jay Inslee, who has since announced his own candidacy. In a statement posted on Twitter, Guardian editor John Mulholland, said Sirota was last published in the newspaper in December, and that Sirota's first contact with the Sanders campaign did not come until mid-January.
Despite ending his work as a journalist, Sirota still presented himself as such well past the time he began informally advising Sanders. Screen captures from his Twitter account from Feb. 21 show that he described himself as a "@CapitalandMain and @GuardianUS journo."
During that trial run advising the campaign, Sirota traveled with a large contingent of the Sanders team to Chicago from New York for the second rally of the campaign's launch weekend.
A review of Sirota's tweets -- captured through the nonprofit Internet Archive's Wayback Machine -- from Feb 20 through this morning shows that Sirota never disclosed his ties to Sanders, but regularly promoted the senator and his campaign. In addition to making critical remarks about President Donald Trump -- who would be Sanders' opponent in the general election -- Sirota attacked other 2020 candidates, including former Colorado Gov. John Hickenlooper and potential third-party hopeful ex-Starbucks CEO Howard Shultz.
He also criticized several other politicians, both Republican and Democrat, including New York Gov. Andrew Cuomo, and both Colorado Sens. Michael Bennet, another potential Democratic presidential candidate, and Cory Gardner, a Republican. Additionally, Sirota was critical of a Boston Globe columnist's coverage of the Sanders launch.
Sirota has a long history of regularly challenging politicians, including many of Sanders' primary opponents. As late as December, he wrote several stories that appeared in the Guardian that were critical of the record of former Texas Rep. Beto O'Rourke, now another 2020 Democratic contender. He also regularly attacked many of the Democratic primary field on Twitter.
For example, he was highly critical of Sen. Cory Booker of New Jersey and his launch for president, writing on Feb. 1, before he started advising Sanders, "I watched @CoryBooker's 'we will rise' video & then remembered that Cory Booker defended Mitt Romney's Wall St firm, attacked the Obama ..."
As of Tuesday morning, Sirota had scrubbed his Twitter page of some 20,000 tweets going back several years. The campaign would not say whether it asked Sirota to delete his old tweets.
The Sirota hire comes alongside a campaign pledge by the Sanders team to run a respectful campaign. Shortly after Sanders announced, the campaign sent their surrogates a letter, from Sanders himself, asking them to not personally attack his opponents.
"As we engage with our opponents in the Democratic primary, we will forcefully present our views and defend ourselves against misrepresentations. But, let us do our very best to engage respectfully with our Democratic opponents -- talking about the issues we are fighting for, not about personalities or past grievances," Sanders wrote. "I want to be clear that I condemn bullying and harassment of any kind and in any space.
In addition to his attacks in the current cycle, Sirota was also a regular critic of Hillary Clinton and her campaign in 2016. He often hammered reporters covering the Clinton campaign, faulting them for not being critical enough of the former secretary of state.
The campaign also hired Briahna Joy Gray, formerly a writer and reporter for outlets such as the Intercept, as national press secretary for Sanders' campaign. Gray has also been fiercely critical of Democrats.