This week, the NPR Politics Podcast investigates defining moments in the lives of four top Democratic presidential candidates to understand how those experiences shape their politics today.Joe Biden's first attempt at running for president — during the 1988 election — ended so quickly that it was still 1987 when he dropped out. But that failure came at the same moment that Joe Biden won a major victory for Democrats: preventing President Reagan's Supreme Court nominee, Robert Bork, from being confirmed. This episode: campaign correspondent Asma Khalid, campaign correspondent Scott Detrow, and White House correspondent Tamara Keith.Connect:Subscribe to the NPR Politics Podcast here.Email the show at nprpolitics@npr.org.Join the NPR Politics Podcast Facebook Group.Subscribe to the NPR Politics Newsletter.Find and support your local public radio station.