There were also concerns about turnout this time, with only a trickle of voters at polling stations visited by AFP in the historic city of Charleston as many people apparently viewed his victory as a foregone conclusion.
Several voters said Mr Biden’s record as president was mostly satisfactory, while admitting there was a lack of enthusiasm for his second-term bid – but that they did not want to see Mr Trump win.
‘Lesser of two evils’
“It’s the lesser of two evils,” said Noelle Paris, 63. “It had to be Biden, just because you know again, the most viable candidate in terms of chances. But strong candidate? Not so much in my opinion.”
But Mr Biden has also been building on momentum after training a series of attacks on Mr Trump.
Other polls have showed him edging ahead of Mr Trump or neck-and-neck, even if his personal approval ratings remain at low levels not seen by a sitting president for decades.
“I think he’s done the best he could,” said Annette Hamilton, 63, casting her vote at a church hall in north Charleston. Asked if Mr Biden could win in November, she replied: “I pray to God he will.”
Mr Biden also pointed to his victory in an unofficial primary in New Hampshire, despite the fact that he was not on the ballot and voters had to write him in.