A doctored video purporting to show Joe Biden addressing a rally and forgetting which state he was in was viewed more than 1.1m times on social media before it was removed from Twitter.
“Hello Minnesota,” the Democratic candidate says as he bounds on to a stage where signs saying “Tampa, Florida” and “Text FL to 30330” are prominently placed.
The footage was clipped from a campaign stop last Friday in St Paul, Minnesota. The signs, however, were fake, added by digital manipulation, according to an Associated Press fact check that debunked the story.
Late on Sunday, Twitter tagged the video, which was posted on a nondescript personal account, as “manipulated media”. Shortly afterwards, with the video having received more than 1.1m views, the user removed it.
While there is no suggestion the video came from the Trump campaign, highlighting Biden’s perceived lack of mental acuity has been a favored tactic for the president and his surrogates.
In March, Donald Trump retweeted a dishonestly edited video that appeared to show Biden, in an appearance in Missouri, endorsing his rival for re-election. That video, also labeled by Twitter as “manipulated”, amassed 6m views.
In September, hundreds of thousands watched an edited video posted by the Trump campaign to YouTube which falsely showed Biden mixing up the words of the pledge of allegiance.
Last week videos were posted of Biden stumbling over some words and using the name George, which Trump supporters seized on as supposed proof the Democrat thought he was running against former Republican president George W Bush.
The reality was Biden was being interviewed by the actor and comedian George Lopez.
The tactic appears at least in part to be working, according to CNN, which quoted an attendee at a Trump rally in Oregon last week.
“He forgets where he’s at, he forgets who he’s running against, he forgets what he’s running for,” the woman said, referring to Biden.
