Channel 4 presents live coverage of the second of three US presidential debates. Over 80 million people watch the first bout between Donald Trump and Hillary Clinton, making it the most watched debate in American history. With the two candidates almost neck and neck in the polls, it's all on the line again with the second encounter taking place at Washington University in St. Louis, Missouri. This time the candidates will be taking questions from the audience as well as discussing topics selected by the moderator. It's set to be another raucous showdown in the race for the presidency.