Donald Trump has been criticised for retweeting a doctored video of Joe Biden supposedly endorsing his re-election – spurring Twitter to use its “manipulated media” warning tag for a video for the first time.

In the clip, originally shared by White House social media director Dan Scavino, Mr Biden first stumbles over his words and then says “we can only re-elect Donald Trump”.

However, in the full clip, the context of Mr Biden’s remarks is clear. Exhorting his audience to ignore attacks from Bernie Sanders and get behind him, he says: “We can only re-elect Donald Trump if in fact we get engaged in this circular firing squad here.”

The selectively edited version of the video has been viewed nearly six million times. After Mr Scavino and Mr Trump shared it, its selectively edited nature drew harsh criticism.

“Disinfo from the Trump campaign. This flagrantly and dishonestly cuts Biden off,” wrote Politico‘s Bill Scher. The Tablet‘s Yair Rosenberg tracked how Mr Trump and his campaign spread the video – and how even a pro-Bernie Sanders account distributed it too.

The Biden campaign, meanwhile, said that Mr Trump’s sharing the video has “made it inescapably clear that he’s terrified of Joe Biden.”

Twitter announced its new policy on “harmful” and misleading tweets in February. It will now remove harmful tweets, meaning those that are intended to suppress voting or threaten people’s safety – but when it comes to misleading or manipulated media, it will simply flag them.

Facebook, meanwhile, was initially criticised for leaving the clip both intact and unflagged. Mr Biden’s campaign issued a statement condemning that decision, calling Facebook’s “malfeasance when it comes to trafficking in blatantly false information” a “national crisis”.

In a statement, a Facebook company spokesperson said that “fact-checkers rated this video as partly false, so we are reducing its distribution and showing warning labels with more context for people who see it, try to share it, or already have. As we announced last year, the same applies if a politician shares the video, if it was otherwise fact checked when shared by others on Facebook”.

After the clip was flagged by Twitter, Mr Scavino retweeted other Trump-friendly users decrying Twitter’s decision. Benny Johnson of conservative campaign group Turning Point USA wrote that “This video was simply shortened. This means every single clip on Twitter is ‘Manipulated’.”

The Trump campaign’s digital director, Gary Coby weighed in too: “#SleepyJoe is such a mess that @Twitter thinks this video was manipulated. Sorry! He actually said this. Not manipulated. They are trying to drag Joe across the finish line.”

Mr Scavino quote-tweeted him with the words “the video was NOT manipulated”.

Mr Trump first nicknamed Mr Biden “Sleepy Joe” in 2019 as he entered the Democratic primary. He and others in his campaign have continued to use the insult ever since, and are now using it to drive home the idea that Mr Biden may be suffering from early-stage dementia – a theory that’s also been applied to Mr Trump himself.

It’s not just Republicans who’ve shared selectively edited footage during the primary.

After his disastrous first TV debate, failed Democratic candidate Michael Bloomberg put out a clip implying he had stumped his rivals by asking if any of them had started a business.