.NO PRESIDENTIAL DEBATE has had as much impact on a political election as that in between Joe Biden and Donald Trump on June 27th. Mr Biden's performance was actually thus dreadful that his own party pressed him to leave. Because Kamala Harris, the vice-president, substituted him as the Democrats' nominee the ethnicity has firmed up. It is now a toss-up, depending on to The Financial expert's style. On September 10th Ms Harris will encounter Mr Trump in a 2nd governmental discussion. Just how much difference will this make?