.NO PRESIDENTIAL discussion has actually possessed as much impact on a vote-casting as that between Joe Biden and Donald Trump on June 27th. Mr Biden's efficiency was actually so tragic that his very own party pressed him to quit. Considering That Kamala Harris, the vice-president, substituted him as the Democrats' candidate the nationality has tightened. It is actually right now a toss-up, depending on to The Economist's model. On September 10th Ms Harris will face Mr Trump in a 2nd presidential controversy. How much difference will this set help make?