.NO PRESIDENTIAL controversy has actually had as much impact on a political election as that between Joe Biden and Donald Trump on June 27th. Mr Biden's efficiency was therefore unfortunate that his very own event pushed him to leave. Considering That Kamala Harris, the vice-president, changed him as the Democrats' candidate the nationality has tightened up. It is right now a toss-up, depending on to The Economist's version. On September 10th Ms Harris will face Mr Trump in a second governmental controversy. How much distinction will this one help make?