Bernie Sanders, Joe Biden, Elizabeth Warren and Pete Buttigieg appear at the start of the Democratic debate at Otterbein University on Oct. 15, 2019 in Ohio. The four enter Tuesday’s debate as the top contenders in Iowa.

Bernie Sanders, Joe Biden, Elizabeth Warren and Pete Buttigieg appear at the start of the Democratic debate at Otterbein University on Oct. 15, 2019 in Ohio. The four enter Tuesday’s debate as the top contenders in Iowa.