This episode contains strong language. Both presidential candidates had clear goals for their first debate on Tuesday. For Joseph R. Biden Jr., the contest was an opportunity to consolidate his lead in polls before Election Day. President Trump’s task was, politically, a taller order — to change the course of a race that he seems to be losing. His tactics for doing that emerged quickly: interrupt and destabilize. The result was a chaotic 90-minute back-and-forth, an often ugly melee in which the two major party nominees expressed levels of acrid contempt for each other. We speak to our correspondent Alexander Burns about the mood and themes of the debate and whether any of it moved the dial for the election. Guest: Alexander Burns, a national political correspondent for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily Background reading: With cross talk, lies and mockery, President Trump made little attempt to reassure swing voters about his leadership. Mr. Biden hit back: “This is so unpresidential.”In his second time moderating a presidential debate, Chris Wallace of Fox News struggled to rein in the president’s behavior.Here are six takeaways from the debate.