Washington | US President Joe Biden has told a key ally that he knows he may not be able to salvage his candidacy if he cannot convince the public in the coming days that he is up for the job, after a disastrous debate performance last week.

The president, who the ally emphasised is still deeply in the fight for reelection, understands that his next few appearances heading into the holiday weekend must go well, particularly an interview scheduled for Friday with George Stephanopoulos of ABC News and campaign stops in Pennsylvania and Wisconsin.