 ABC News. I'm Sherry Preston. The White House announcing last night that President Biden has been diagnosed with COVID. The president said to be isolating and still insisting he is not backing down in the reelection campaign. Adamant, he is the candidate who beat Donald Trump before and will do it again. Others, though, including former House Speaker Nancy Pelosi, said to have told Biden last week she and other Democrats are concerned about him staying in the race. At the Republican National Convention last night, Donald Trump's vice presidential pick took the stage.