 The vice president, as their preferred candidate, earlier this week reports emerged that Barack Obama had joined other high-profile Democrats in privately expressing their concerns about Mr Biden's ability to win in the presidential election in November. Meanwhile, the president of his campaign insists that he will return to the campaign trail next week, having self-isolated, having been diagnosed with COVID. Just before we came on air, I spoke to Julia Manchester, who's national political reporter for the news website The Hill.