Democratic debate in New Hampshire

Democratic presidential candidates entrepreneur Andrew Yang, from left, former South Bend, Ind., Mayor Pete Buttigieg, Sen. Elizabeth Warren, former Vice President Joe Biden, Sen. Bernie Sanders, Sen. Amy Klobuchar and businessman Tom Steyer stand on stage Friday for the Democratic presidential primary debate hosted by ABC News, Apple News and WMUR-TV at St. Anselm College in Manchester, N.H.   (Charles Krupa / Associated Press)

Former Vice President Joe Biden, left, embraces Sen. Bernie Sanders during the Democratic presidential primary debate on Friday in Manchester, N.H.  (Elise Amendola / Associated Press)

Democratic presidential candidates Sen. Elizabeth Warren (D-Mass.), left, and Sen. Amy Klobuchar (D-Minn.) greet each prior to the start of the Democratic presidential primary debate at St. Anselm College on Friday in Manchester, N.H.  (Joe Raedle / Getty Images)

Former South Bend, Ind., Mayor Pete Buttigieg, left, shakes hands with businessman Tom Steyer.  (Charles Krupa / Associated Press)

Former South Bend, Ind., Mayor Pete Buttigieg, right, and his husband, Chasten Buttigieg, shake hands with members of the audience after the Democratic presidential primary debate.  (Elise Amendola / Associated Press)

ABC’s George Stephanopoulos and Linsey Davis address members of the audience Friday before the start of a Democratic presidential primary debate hosted by ABC News, Apple News and WMUR-TV at St. Anselm College in Manchester, N.H.   (Charles Krupa / Associated Press)

Sen. Amy Klobuchar (D-Minn.) waves before the start of the Democratic presidential primary debate Friday hosted by ABC News, Apple News and WMUR-TV at St. Anselm College in Manchester, N.H.   (Charles Krupa / Associated Press)

Democratic presidential candidate Sen. Bernie Sanders (I-Vt.) waves as he takes the stage Friday before the Democratic debate begins at St. Anselm College in Manchester, N.H.   (Charles Krupa / Associated Press)

Pete Buttigieg, former South Bend, Ind., mayor and Democratic presidential candidate, waves as he takes the stage Friday for the Democratic debate at St. Anselm College in Manchester, N.H.  (Charles Krupa / Associated Press)

Democratic presidential candidates former South Bend, Ind., Mayor Pete Buttigieg, second from left, shakes hands with Sen. Amy Klobuchar as Sen. Bernie Sanders, left, and former Vice President Joe Biden and Sen. Elizabeth Warren look on before the start of Friday’s Democratic presidential primary debate hosted by ABC News, Apple News, and WMUR-TV at St. Anselm College in Manchester, N.H.   (Charles Krupa / Associated Press)

Sen. Elizabeth Warren (D-Mass.) addresses former Vice President Joe Biden during the Democratic presidential primary debate Friday at St. Anselm College in Manchester, N.H.   (Elise Amendola / Associated Press)

Former Vice President Joe Biden speaks during the Democratic presidential primary debate Friday at St. Anselm College in Manchester, N.H.  (Elise Amendola / Associated Press)