US Vice President Kamala Harris and former president Donald Trump will face off in a debate for the first time on Tuesday, each seeking an edge in what has become a neck-and-neck race for the White House. After weeks of back-and-forth on the where, when and how of the debate, US broadcaster ABC — which is hosting the event — announced the final rules of the contest, as agreed to by the two campaigns, this week. Here are the major takeaways. The debate will take place at the National Constitution Center in Philadelphia at 9:00 pm local time Tuesday (0100 GMT Wednesday,) and will be aired live. There will be no audience present in the room. The event will be moderated by ABC anchors David Muir and Linsey Davis, and will run for 90 minutes of debate time, with two commercial breaks. The issue of whether microphones would be muted — as they were during a previous debate between US President Joe Biden and Trump — was a contentious one, with each side accusing the other of cowardice over the question. ABC has announced that each candidate’s microphone will only be live for when it is their turn to speak, and muted when the time belongs to the other candidate. Only moderators will be allowed to ask questions, and no topics or questions will be shared in advance with the candidates. Candidates will not offer opening statements. They will be allotted two minutes to answer each question, with two minutes granted to their opponent for a rebuttal. There will be an additional minute for “a follow-up, clarification, or response,” according to the rules.