Our worldwide cover this week explained why Joe Biden must withdraw from the presidential race. The debate was awful for him, but the cover-up has been worse. It was agony to watch a befuddled old man struggling to recall words and facts. But the operation by his campaign to deny what tens of millions of Americans saw with their own eyes is more toxic than either, because its dishonesty provokes contempt.

Democrats argue, rightly, that Mr Trump is unfit to be president. But the debate and its aftermath have proved Mr Biden unfit, too. First, because of his mental decline. Second, because of his insistence, abetted by his family, senior staff and Democratic elites, that he is still up to the world’s toughest job. Mr Biden’s claim that this election is between right and wrong is ruined by the fact that the existence of his campaign now depends on a lie. He deserves to be remembered for his accomplishments and his decency rather than his decline. Senior Democrats must call for change. It is not too late.