Democrats spar on healthcare, some urge civility

Thursday's Democratic presidential debate in Houston started off with a bang, as top contenders Joe Biden, Elizabeth Warren and Bernie Sanders wasted no time sparring on healthcare, an issue that's opened the deepest divide among Democrats in the battle for the party's nomination.

The #2 and #3 challengers essentially tag-teamed the former vice president, pushing a Medicare for All proposal, while Biden defended his plan to build on Obamacare and accused his more progressive rivals of wanting to tear it down.

(SOUND BITE) (ENGLISH) MASSACHUSETTS SENATOR ELIZABETH WARREN, SAYING:

"I'm not here to criticize anyone."

But it wasn't the Warren-Biden grudge match many had expected.

Instead, it was underdog Julian Castro who took on the frontrunner, accusing the 76-year-old of forgetting what he had just said two minutes earlier - a comment many saw as a knock on Biden's age, and one some in the audience booed.

(SOUND BITE) (ENGLISH) FORMER U.S. HOUSING SECRETARY JULIAN CASTRO, SAYING:

"We had a disagreement about healthcare policy."

(SOUND BITE) (ENGLISH) REPORTER, SAYING:

"Do you think it went too far?"

(SOUND BITE) (ENGLISH) FORMER U.S. HOUSING SECRETARY JULIAN CASTRO, SAYING:

"No."

The heated exchange prompted other candidates to call for civility, including entrepreneur Andrew Yang.

(SOUND BITE) (ENGLISH) ENTREPRENEUR ANDREW YANG, SAYING:

"Certainly, it was uncomfortable to be standing there while it was happening."

And South Bend, Indiana, Mayor Pete Buttigieg and Minnesota Senator Amy Klobuchar warned that too much acrimony would distract them from the real goal: defeating President Donald Trump in 2020.

(SOUND BITE) (ENGLISH) CALIFORNIA SENATOR KAMALA HARRIS, SAYING:

"Donald Trump has been a failed president, a failed administration with broken promises."

California Senator Kamala Harris spent most of her time attacking Trump, even addressing him directly in her opening statement, saying "we all know he's watching."

He wasn't. In fact, he was competing for air time, giving a televised speech at a House Republican dinner in Baltimore, where he forwent civility.

(SOUND BITE) (ENGLISH) U.S. PRESIDENT DONALD TRUMP, SAYING:

"Crazy Bernie, he is a crazy guy... I hit Pocahontas way too early... Sleepy Joe, he's falling asleep. He has no idea what the hell he's doing or saying... You think Buttigieg is winning Texas? I've had him up to here."

But perhaps the standout moment at the Democrats' third presidential debate came from former congressman Beto O'Rourke, who has seized on the issue of gun violence since two mass shootings in his home state of Texas.

When asked if he was going to take away people's guns, he said: "Hell yes, we're going to take your AR-15" - a phrase his campaign team soon had ready to sell on T-shirts.