Candidates face off in third Democratic debate in Houston

Security staffers corral protesters during the debate at Texas Southern University.  (Win McNamee / Getty Images)

Minnesota Sen. Amy Klobuchar and New Jersey Sen. Cory Booker.  (Robyn Beck / AFP/Getty Images)

Cory Booker smiles for photos before the audience during a break.  (Win McNamee / Getty Images)

Sen. Kamala Harris recalls the late Sen. John McCain’s thumbs-down vote that defeated President Trump’s effort to repeal Obamacare.   (David J. Phillip / Associated Press)

Sen. Cory Booker responds to a question.  (David J. Phillip / Associated Press)

Former Vice President Joe Biden and Sen. Elizabeth Warren during a break.   (David J. Phillip / Associated Press)

Former Texas Rep. Beto O’Rourke, right, listens to Andrew Yang.  (David J. Phillip / Associated Press)

Beto O’Rourke makes a point.   (Win McNamee / Getty Images)

Joe Biden listens as Elizabeth Warren speaks.   (David J. Phillip / Associated Press)

Bernie Sanders and Joe Biden.   (David J. Phillip / Associated Press)

Joe Biden is flanked by Bernie Sanders and Elizabeth Warren.   (David J. Phillip / Associated Press)

From left, Joe Biden, Elizabeth Warren, Kamala Harris, Andrew Yang and Beto O’Rourke before the debate.   (Eric Gay / Associated Press)

From left, Sen. Amy Klobuchar, Sen. Cory Booker, South Bend Mayor Pete Buttigieg, Sen. Bernie Sanders, former Vice President Joe Biden, Sen. Elizabeth Warren, Sen. Kamala Harris, entrepreneur Andrew Yang, former Texas Rep. Beto O’Rourke and former Housing Secretary Julian Castro.  (David J. Phillip / Associated Press)

From left, Sen. Amy Klobuchar, Sen. Cory Booker, South Bend Mayor Pete Buttigieg, Sen. Bernie Sanders, former Vice President Joe Biden, Sen. Elizabeth Warren, Sen. Kamala Harris, entrepreneur Andrew Yang, former Texas Rep. Beto O’Rourke and former Housing Secretary Julian Castro are introduced.  (Eric Gay / Associated Press)

The 10 candidates take the stage before Thursday’s debate.   (Eric Gay / Associated Press)

From left, Bernie Sanders, Joe Biden and Elizabeth Warren.   (David J. Phillip / Associated Press)

Bernie Sanders, Joe Biden and Elizabeth Warren.   (Eric Gay / Associated Press)

Bernie Sanders and Joe Biden before the debate.   (David J. Phillip / Associated Press)

Elizabeth Warren and Kamala Harris.   (David J. Phillip / Associated Press)

Audience members take their seats before the Democratic presidential primary debate Thursday, Sept. 12, 2019, at Texas Southern University in Houston.  (Associated Press)