Latest Iowa caucus poll has a new leader

Support for Sen. Elizabeth Warren has dropped by nearly 10% over the past month, according to the latest Iowa State University/Civiqs poll of Democratic presidential candidates. This shift has helped propel Mayor Pete Buttigieg to the top of the poll, with 26% of those surveyed selecting Buttigieg as their top choice. Iowa State political science professor Dave Peterson talks about the change in voter preference and other poll results.