Part 2 of our series on pivotal moments in the lives of the 2020 Democratic presidential contenders. Michael Barbaro speaks with Bernie Sanders, the democratic socialist senator from Vermont.  Mr. Sanders reflected on his early schooling in politics and how he galvanized grass-roots support to evolve from outraged outsider to mainstream candidate with little shift in his message. Guest: Bernie Sanders, the Vermont senator and candidate for the 2020 Democratic presidential nomination. We also speak with Alexander Burns, who covers national politics for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily.  Background reading:Mr. Sanders has staked his presidential campaign, and much of his political legacy, on transforming health care in America. His mother’s illness and a trip he made to study the Canadian system help explain why.We asked 21 candidates the same 18 questions. Hear Mr. Sanders’s answers.

Part One in our series on pivotal moments in the lives of the 2020 presidential front-runners. In studio with “The Daily,” Pete Buttigieg, the mayor of South Bend, Ind., talks about how his lifelong political ambitions were complicated by the secret he kept for decades. Guests: Pete Buttigieg, mayor of South Bend, Ind., and 2020 Democratic presidential candidate.Jeremy W. Peters, a politics reporter in the Washington bureau of The New York Times.