The prospect of another Democrat replacing Joe Biden as the party’s presidential nominee is minimal, a political expert has claimed. The 81-year-old is the country’s oldest ever sitting president and his ability to carry out the job for another four years has been thrown into question after a series of gaffes. But Biden insists he remains as capable as ever, and the US President will be emboldened by a lack of alternatives, according to James Johnson. He told GBN America that nobody is in the offing, and his Vice President also poses very little danger. “It’s something that I think a lot of pe…