.NO PRESIDENTIAL DEBATE has actually had as much effect on a political election as that between Joe Biden as well as Donald Trump on June 27th. Mr Biden's functionality was actually therefore dreadful that his personal celebration pressed him to quit. Because Kamala Harris, the vice-president, substituted him as the Democrats' candidate the nationality has tightened up. It is currently a toss-up, depending on to The Economist's design. On September 10th Ms Harris are going to encounter Mr Trump in a 2nd presidential debate. Just how much difference will this create?