 Since his feeble debate performance, multiple polls have shown that both Mr. Biden's approval rating and his chance of beating Mr. Trump have markedly dropped from their already shaky levels. In response, he's adopted a favorite theme of the floundering politician, insisting the polls are wrong and showing that his presidency is historically unpopular. Even if the polls were off by historic amounts, it would still show overwhelming skepticism about his fitness. He's denied that age is diminishing his abilities. Not even bringing up the subject in a lengthy letter to congressional Democrats.