A week before Iowa caucuses, which 2020 Democrats are resonating most?
As Iowa's Democratic caucuses approach, Vermont Sen. Bernie Sanders' message seems to be resonating with voters, though he still faces concerns he is too liberal to defeat President Trump. Along with Sens. Elizabeth Warren and Amy Klobuchar, he dashed to Iowa to campaign during a break from Trump's impeachment trial. Also there was Pete Buttigieg, who touted his electability. John Yang reports.