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.On December 10th, 2010, Bernie Sanders gave a marathon speech on the floor of the Senate protesting a tax deal negotiated between Senate Majority Leader Mitch McConnell and then-Vice President Joe Biden. Sanders was upset that the package included tax cuts for high-income Americans.Though his speech failed to sway hearts and minds in the Senate — the deal passed with a bipartisan super-majority — but gained traction online and to helped establish Bernie Sanders as a progressive standard-bearer.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.