Twitter came under fire on Tuesday for allowing President Trump to tweet conspiracy theories about Joe Scarborough and the 2001 death of one of his staffers, despite the objections of the staffer's family. The company came under further fire from Trump himself for fact-checking two of his tweets about mail-in voting.

Dan and the New York Times' Kara Swisher dig into Trump’s use of the platform and Twitter’s steps — and missteps — in handling it.

Go deeper: Trump has turned Big Tech's speech rules into a political football

Twitter made headlines Tuesday after labeling two election-related tweets from President Trump as potentially misleading — the company’s first action against the president’s tweets, which often test its policies on misinformation and abuse.

The big picture: Twitter's unprecedented move, which swiftly drew Trump's fury, was just one of four controversies over the last 24 hours involving tech platforms grappling with free speech issues. And all of them, Axios' Sara Fischer and I report, reflect what a partisan issue the policing of social media content has become.

President Trump threatened to shut down or regulate social media platforms due to anti-conservative bias in a pair of Wednesday tweets — the day after Twitter's first fact-check against the president's claims on its platform.

Reality check: While his claim that social media companies target conservatives isn't new, an Axios analysis last year found that stories about the 2020 presidential election that drove the most engagement online often came from right-wing media outlets.

Twitter fact-checked two of President Trump's unsubstantiated tweets that mail-in ballots in the 2020 election would be fraudulent for the first time on Tuesday, directing users to "get the facts" through news stories that cover the topic.

Why it matters: Twitter and other social media platforms have faced criticism for not doing enough to combat misinformation, especially when its propagated by the president.

The husband of Lori Klausutis, an aide to Joe Scarborough when he was a member of Congress who died in 2001, asked Twitter CEO Jack Dorsey to take down President Trump's tweets baselessly accusing the MSNBC host of murdering her, according to a letter obtained by the New York Times' Kara Swisher.

The state of play: Timothy Klausutis asked Dorsey to delete the tweets because Trump "has taken something that does not belong him — the memory of my dead wife and perverted it for perceived political gain."

The major online platforms' long struggle to cope with floods of misinformation has reached a new pitch of urgency during the coronavirus pandemic — just as the fight has become harder than ever.

Driving the news: In the most recent controversy, One America News Network — a small rival to Fox News that is President Trump's current favorite — aired a segment Friday, also posted on YouTube, that makes conspiracy-theory-style connections between China, the "deep state," George Soros, Bill Gates, and the Clintons.

Of all the conspiracy theories floating around the internet related to the coronavirus, disinfectant has by far gone the most viral.

Why it matters: Unlike some of the other conspiracy theories gaining traction on the internet, the disinfectant theory has gone viral online in large part because it's so obviously nonsensical that it quickly became an internet meme after President Trump suggested it could be used as a cure for coronavirus.

Fear of the coronavirus and misinformation about the pandemic have created a pool of targets for online scammers.

The big picture: Misinformation around COVID-19 is rampant online, from phony cures to outlandish claims that 5G wireless signals cause the illness. Cybersecurity analysts are also seeing an explosion in phishing and other digital cons that base their scams on these popular coronavirus myths.

YouTube's product chief tells Axios that the Google-owned video site has removed thousands of COVID-19 videos — including some from the Brazilian president's channel — for violating policies related to the spread of medical misinformation.

Why it matters: Though criticized in the past for allowing misinformation to flourish, Facebook, Google and Twitter have all been taking a tougher stand when it comes to the coronavirus.

It's notable that Twitter, like other social networks, has announced stricter rules on virus-related misinformation than other types of false posts. Even more notable, though, is that Twitter has actually enforced its rules against prominent accounts in recent days.

Why it matters: Twitter has been criticized for being lax to enforce its rules, particularly against well-known politicians and celebrities.