Democratic presidential primary debate in Iowa

President Donald Trump supporter Gary Leffler, of West Des Moines, Iowa, sits on his tractor as he talks with Carol Dunitz, of Ann Arbor, Mich., outside the debate hall.

From left, Democratic presidential candidates businessman Tom Steyer, Sen. Elizabeth Warren, D-Mass., former Vice President Joe Biden, Sen. Bernie Sanders, I-Vt., former South Bend Mayor Pete Buttigieg, and Sen. Amy Klobuchar, D-Minn., stand on stage.

Democratic presidential candidates Sen. Elizabeth Warren, D-Mass., left, and Sen. Bernie Sanders, I-Vt., right greet each other as former Vice President Joe Biden, watches.

Democratic presidential candidate Sen. Amy Klobuchar, D-Minn., answers a question as candidate former South Bend Mayor Pete Buttigieg listens.

Democratic presidential candidate businessman Tom Steyer answers a question as Sen. Elizabeth Warren, D-Mass. raises her hand.

Democratic presidential candidate Sen. Bernie Sanders, I-Vt., right, speaks to Sen. Elizabeth Warren, D-Mass., left, as former Vice President Joe Biden listens.

Democratic presidential candidate Sen. Amy Klobuchar, D-Minn., speaks.

Democratic presidential candidates Sen. Elizabeth Warren, D-Mass., left, and former Vice President Joe Biden talk during a break.

Democratic presidential candidate Sen. Bernie Sanders, I-Vt.,, center, speaks as fellow candidates businessman Tom Steyer, from left, Sen. Elizabeth Warren, D-Mass., former Vice President Joe Biden, former South Bend Mayor Pete Buttigieg and Sen. Amy Klobuchar, D-Minn. listen.