Over the next two days, 20 Democrats will take the stage for the first debates of the 2020 presidential race. We look at the competing visions for America they’ll be fighting over this week, and throughout the campaign. Guest: Alexander Burns, who covers national politics for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily.  Background reading: Does anyone deserve to have a billion dollars? How many hours of sleep do you get? The Times asked 21 Democratic presidential candidates the same set of questions. Here’s what they said, and here are some takeaways.For the candidates, these early debates may represent the first, best — and, in some cases, only — opportunity to stand out from competitors and build national momentum in the primary. Here’s how they’re preparing.Senator Elizabeth Warren is the only candidate on the first night who is polling in double digits, but there are plenty of story lines and political dynamics to watch for.