
Democrats unleashed their most direct and personal attacks on one another of the 2020 election during Thursday night's presidential debate in Houston, with attacks based on age, ideology, and the legacy of Barack Obama.

With increased urgency of top-tier candidates to distinguish themselves, and for lower-tier candidates to rise to close the gap from behind the top three poll leaders, contenders threw jabs in multiple directions at the third debate, with health policy as the chief battleground.

Sanders went after Biden early on for having attacked his own Medicare for All plan for its explosive $30trillion price tag, claiming the status quo would cost even more.

'Well, let me tell you something, for a socialist, you got a lot more confidence in corporate America than I do,' Biden told Sanders, a self-described Democratic Socialist who caucuses with Senate Democrats.

Former Housing Secretary Julián Castro, 44, tore into Biden, 76, appearing to question his memory during an angry attack.

Biden said: 'If you want Medicare, if you lose the job from your insurance company, from your employer, you automatically can buy into this. You don't have no pre-existing condition can stop you from buying in. You get covered. Period.'

Castro responded in high dudgeon, looking directly at Biden – who like him served during the Obama administration.

'Are you forgetting what you said two minutes ago? Are you forgetting already what you said just two minutes ago? I can't believe that you said two minutes ago that they had to buy in, and now you're saying they don't have to buy in. You're forgetting that,' Castro said.

It was not immediately clear what he meant by his attack, but it prompted an immediate lecture from the youngest candidate on stage, Pete Buttigieg, 37.

'This is why presidential debates are becoming unwatchable. This reminds everybody of what they cannot stand about Washington: scoring points against each other, poking at each other and telling each other that you're, my plan …' Buttigigeg lectured.

'Yeah, that's called a Democratic primary election. That's called an election. That's an election, you know? This is what we're here for,' Castro interjected.

Klobuchar jumped in: 'Yeah, but a house divided cannot stand.'

The outsider candidate Andrew Yang had his say. 'Look, everyone, we know we're on the same team here. We know we're on the same team.'

Democratic presidential candidates(L-R) Sen. Amy Klobuchar (D-MN), Sen. Cory Booker (D-NJ), South Bend, Indiana Mayor Pete Buttigieg, Sen. Bernie Sanders (I-VT), former Vice President Joe Biden, Sen. Elizabeth Warren (D-MA), Sen. Kamala Harris (D-CA), former tech executive Andrew Yang, former Texas congressman Beto O'Rourke, former housing secretary Julian Castro took the stage for the Democratic Presidential Debate at Texas Southern University's Health and PE Center on in Houston, Texas, Thursday

A three-way tiff between Bernie Sanders, Joe Biden and and Elizabeth Warren on healthcare was set off with the three frontrunners for the nomination snapping back and forth at one another

Vice President, a moderate, brandished the 'socialist' label against rival Bernie Sanders during an angry exchange after he was asked if the most liberal members of the presidential field were pushing too far in their Medicare for All healthcare plan

California Sen. Kamala tried going after Biden – who she had ripped during the first debate over school bussing – after moderates asked her a question quoting his previous criticism of her claim to use executive orders to push gun control.

'Some things you can, many things you can't,' the former vice president jumped in to tell her.

Harris responded by trying to seize the Obama legacy. 'Hey Joe, instead of saying, "No we can't" let's say, "Yes we can,"' she said.

She drew chuckles and even a rejoinder from the moderator when she delivered an odd line where she tried to mock President Donald Trump for being outmatched by Chinese President Xi Jinping in a trade war that has rattled markets and pinched farmers.

'The bottom line is this: Donald Trump, in office on trade policy, you know, he reminds me of that guy in 'The Wizard of Oz,' you know? 'When you pull back the curtain, it's a really small dude?' she said, getting a laugh during a prolonged pause.

'Okay … I'm not even going to take the bait, Senator Harris,' quipped the 5 ft. 5 inches George Stephanopoulos.

'Oh George it wasn't about you!' Harris interjected, chuckling.

Minnesota Sen. Amy Klobuchar, a relative centrist among the stage, was one of the first to take on extremes as the 'noise and the nonsense' of the campaign trail.

She went after Sanders, who exhorted that he 'wrote the damn bill,' in reference to Medicare for All. Sanders championed the issue in his failed 2016 primary campaign against Hillary Clinton, only to have the issue become a mantra on the party's left during the current contest.

'While Bernie wrote the bill, I read the bill,' Klobuchar said. 'And on Page 8 of the bill it says we will no longer have private insurance as we know it. And that means 149 million Americans will no longer be able to have their current insurance,' she added.

It was one of several times she tried to use humor to make a point after rolling out a 'Houston, we have a problem' line in her opening script. Later, she spoke forcefully about her legislation 'to make sure domestic abusers don't get AK-47s.'

Former Housing secretary Julián Castro, 44, tore into Biden, 76, appearing to question his memory during an angry attack

Sen Amy Klobuchar got the night's first laugh lines when she said: 'Houston, we have a problem,' and accused Trump of running the country 'like a game show'. Kamala Harris spoke directly to Donald Trump in her opening statement, telling him he can 'go back to watching Fox News'

Things took a turn to gameshow politics during opening statements when entrepreneur Andrew Yang invited viewers to go to his website to apply for a $10,000 giveaway from his campaign funds, prompting laughter from Pete Buttigieg

Sen. Cory Booker of New Jersey also got in a laugh, when co-host Jorge Ramos asked the vegan senator whether he would encourage Americans in other states to follow his lead.

'First of all I want to say: no,' Booker responded. 'I want to translate that into Spanish: No,' he quipped.

He also tried to position himself as a unifier on stage who would still undo the Trump legacy.

'This must be a moment where we as Democrats can begin to show that we cannot only stake and stand our ground, but find common ground, because we've got one shot to make Donald Trump a one-term president,' said Booker.

'If I am president of the United States, we will create an office in the White House to deal with the problem of white supremacy and hate crimes and we will make sure that systemic racism is dealt with in substantive plans,' said Booker, who noted he lives in a racially mixed part of Newark.

When the dust cleared, there was no clear stand-out victor. Biden once again took blows from his competitors, but avoided a devastating attack like the one launched by Harris in Miami. When Castro went after him, the amped-up attack did not appear connected to any major lapse, and if it was no other candidate picked up against it against a popular figure in Democratic politics.

Warren hung back for stretches of the dialogue, raising her hand to issue forceful remarks about education, and getting in her early stint as a public school teacher in Houston before rounding out her academic career at Harvard (a part she glossed over). She did engage in a full-on Biden attack that some pundits had been predicting.

Sanders got to deliver an extended take on his own definition of Democratic Socialism after Ramos asked him a question about Venezuela. But he also had to endure Biden's direct ideological attack and once again field criticism that his plans could run up trillions in costs.

Despite the admonitions to focus on Trump, several parts of the president's record were left untouched on stage. On a day when the House Judiciary Committee voted on rules for impeachment, no one brought up removing the president through means other than the ballot box.

Although Trump's health and other policies came under fire, would-be opponents failed to bring up his tax cut, the deficit hitting $1 trillion for the current year, the president's recent failed effort to buy Greenland, questions over his mental capacity, and the Sharpie-gate saga, alleged self-dealing at the president's golf properties, or his race-freighted attacks on fellow-Democrats.

Beto O'Rourke did inveigh: 'But we will also call out the fact that we have a white supremacist in the White House and he poses a mortal threat to people of color all across this country.'

Businessman Andrew Yang had a new take on his pitch for a $1,000 dividend for every American – inviting viewers to go to his website to apply for a $10,000 giveaway from his campaign funds.

The line provoked a visible smirk, followed by a smile from South Bend Mayor Pete Buttigieg.

'It's original, I'll give you that,' said the fresh-faced Midwesterner, who has been struggling to break into the upper ranks of the field.

Although it was Yang who put forth a cash-giveaway, it was Klobuchar who got in one of the night's first laugh lines when she said: 'Houston, we have a problem,' and accused Trump of running the country 'like a game show.'

Sen. Kamala Harris tried to get President Trump's goat, speaking directly to him in her opening remarks.

She told him 'the only reason you have not been indicted' was internal Justice Department guidelines.

'But here's what you don't get,' she tried to school him. 'What you don't get is that the American people are so much better than this.'

When she was done, she rapped him: 'And now, President Trump, you can go back to watching Fox News, to applause.

The first question of the debate was designed to tee-off the main conflict of the night: the fight between the moderate and liberal wings of the party.

And it set off a three-way tiff between Biden, Warren and Sanders on healthcare with the three frontrunners for the nomination snapping back and forth at one another.

Biden brandished the 'socialist' label against rival Bernie Sanders during an angry exchange at the debate.

Biden, whose Democratic support tends to skew toward moderate voters while Sanders and Warren enjoy more support among the party's left flank, pulled out the attack during a heated exchange over health care, after going after Sanders for his 'Medicare for All' bill.

'The option I'm proposing is Medicare for All – Medicare for Choice,' Biden said, at first stumbling over his own proposal.

'If you notice, nobody yet said how much it's going to cost the taxpayer,' Biden told the audience, after Sanders had already attacked his own plan for its cost.

'My friend from Vermont thinks that the employer is going to give back if you negotiate as a union all these years, got a cut in wages because you got insurance. They're going to give back that money to the employee?' Biden asked him.

'As a matter of fact, they will,' Sanders interjected.

Thursday marked the first time Biden and Warren were on the same debate stage and the all eyes were on how the two would handle their policy conflicts

The 10 candidates were quick to take jabs at President Trump and one another with attacks based on age, ideology, and the legacy of Barack Obama

President Trump regularly brandishes the 'socialist' label to go after Democrats generally, as well as members of the 'squad.'

A Trump campaign email sent minutes before the debate began: 'The BIG GOVERNMENT SOCIALISTS are trying to take back our Nation.'

Sanders began the debate by going after Biden for attacking his plan for costing $30 trillion and ending private health insurance.

'Joe said that Medicare for All would cost over $30 trillion. That's right, Joe. Status quo over ten years will be $50 trillion. Every study done shows that Medicare for all is the most cost-effective approach to providing health care to every man, woman and child in this country,' he said.

'I wrote the damn bill, if I may say so,' he added, using one of his best attack lines. 'I'll tell you how absurd the system is tonight on ABC, the health care industry will be advertising, telling you how bad Medicare for all is, because they want to protect their profits.'

Biden snapped back that the middle class would pay more taxes under Medicare for All.

'The middle class person, someone making 60 grand with three kids, they're going to pay $5,000 more. They're going to pay 4 per cent more on their income tax. That's a reality. That's not a bad idea if you like it. I don't like it,' he said.

Biden said: 'I think the Obamacare worked. I think in the way we add to it, add a public option, guarantee that everyone will be able to have affordable insurance,' he said defending the plan passed when he was Barack Obama's vice president.

He then he pivoted to attacking Warren, who has gained on him in the polls for the nomination, on the costs of the plan.

'My plan for health care costs a lot of money. It costs $740billion. It doesn't cost $30trillion. $30trillion a year, it turns out, is twice what the entire federal budget is. That's before - as it exists now, without interest on the debt. How are we going to pay for it? I want to hear that tonight. My distinguished friend, the senator on my left, has not indicated how she pays for it,' he said.

Thursday marked the first time Biden and Warren were on the same debate stage and the all eyes were on how the two would handle their policy conflicts.

Candidates Biden, Booker and Harris praised Beto O'Rourke for his response to the August shooting a Wal-Mart in his home town of El Paso where a mass shooter killed 22 people and injured 24 others

New Jersey Senator Cory Booker spoke passionately about gun violence, saying he 'will fight this and bring a fight to the NRA and the corporate gun lobby like they have never seen before'

Fresh issues that might lend itself to debate questions or candidate zingers are sharpie-gate, more White House staff departures, Trump's cancelled trip to Poland, and his failed effort to buy Greenland

Warren responded by giving credit to Obama, who Biden mentions frequently on the campaign trail, and then explaining that the wealthy would pay for her plan.

'We all owe a huge debt to President Obama, who fundamentally transformed health care in America and committed this country to healthcare for every human being. And now the question is, how best can we improve on it? And I believe the best way we can do that is we make sure that everybody gets covered by health care at the lowest possible cost. How do we pay for it? We pay for it, those at the very top, the richest individuals and the biggest corporations, are going to pay more. And middle class families are going to pay less. That's how this is going to work,' she said.

Warren jumped in to attack healthcare companies.

'So, let's be clear, I've actually never met anybody who likes their health insurance company. I've met people who like their doctors, I met people who like their nurses, I've met people who like their pharmacists, I met people who like their physical therapists. What they want is access to health care. And we just need to be clear about what Medicare for all is all about. Instead of paying premiums into insurance companies and then having insurance companies build their profits by saying no to coverage, we're going to do this by saying, everyone is covered by Medicare for all, every health care provider is covered. And the only question here in terms of difference is where to send the bill,' she said.

'Let us be clear, Joe, in the United States of America, we have spending twice as much per capita on health care as the Canadians or any other major country on Earth,' Sanders added.

'This is America,' Biden responded.

The bickering continued when candidates were asked about their response to the recent spate of mass shootings that have taken place in the country.

Biden was asked why voters should trust him to lead on the issue when President Obama asked him to work on background checks after the 2012 Sandy Hook Elementary School shootings and a measure to expand the checks died on the Senate floor.

'Because I've got it done before,' the former vice president said. 'I'm the only one up here that's ever beat the NRA. Only one to beat the NRA nationally. I brought the Brady bill into focus and became law. And so, that's number one. Number two, after Sandy Hook, a number of things happened. It went from a cause to a movement,' he said.

The Brady Bill that Biden referred to was a 1993 law signed by President Bill Clinton was Biden was a senator from Delaware. It mandated federal background checks on firearm purchasers in the United States, and imposed a five-day waiting period on purchases, until the NCIC system was implemented in 1998.

'So, the point is, things have changed,' Biden said, 'and changed a lot.'

Debate moderators (L-R) David Muir of ABC News, Jorge Ramos of Univision, Linsey Davis of ABC News, and George Stephanopoulos of ABC News appear on stage before the Democratic Presidential Debate at Texas Southern University's Health and PE Center in Houston, Texas

California Sen. Kamala tried going after Biden – who she had ripped during the first debate over school bussing – after moderates asked her a question quoting his previous criticism of her claim to use executive orders to push gun control

He then went on to praise Beto O'Rouke for his response to the August shooting a Wal-Mart in his home town of El Paso where a mass shooter killed 22 people and injured 24 others.

'By the way, the way Beto - forgive me for saying Beto, congressman,' Biden said to O'Rourke.

'That's okay. Beto's good,' O'Rourke responded.

'The way he handled what happened in his hometown is meaningful. To look into the eyes of those people, to see those kids, to understand those parents, you understand the heartache,' Biden said.

But Biden was also asked why he said assault weapons cannot be outlawed for purchase by executive order.

'Some things you can. Many things you can't,' Biden said.

But Harris attacked him, using Barack Obama's 2008 campaign slogan.

'Well, I mean, I would just say, hey, Joe, instead of saying, no, we can't, let's say yes, we can,' the California senator said.

'And yes, we can,' she added. 'It is overlooking the fact that every day in America, our babies are going to school to have drills. Elementary, middle and high school students, where they are learning about how they have to hide in a closet or crouch in a corner if there is a mass shooter roaming the hallways of their school. I was talking about this at one of my town halls and this child was 8 years old, probably, came up to me. It was like it was a secret between the two of us, he tugged on my jacket and he said, I had to have one of those drills. It is traumatizing our children.'

She then praised O'Rourke for his work in El Paso and got in an attack at President Trump.

'Beto, God love you for standing to courageously in the midst of that tragedy. People asked me in El Paso, they said, you know, because I have a long-standing record on this issue. They said, do you think Trump is responsible for what happened? And I said, well, look, obviously he didn't pull the trigger, but he certainly been tweeting out the ammunition,' Harris said.

O'Rourke then got heated talking about the need to eliminate assault weapons after the mass shootings in El Paso and Odessa in a passionate speech that had the audience cheering him on.

'If it's a weapon that was designed to kill people on a battlefield. If the high impact, high velocity round, when it hits your body, shreds everything inside of your body because it was designed to do that so you would bleed to death on a battlefield and not be able to get up and kill one of our soldiers. When we see that being used against children and in Odessa, I met the mother of a 15-year-old girl who was shot by an AR-15 and that mother watched her bleed to death over the course of an hour because so many other people were shot by that AR-15 in Odessa, there weren't enough ambulances to get to them in time. Hell, yes, we're going to take your AR-15, your AK-47. We're not going to allow it to be used against a fellow American anymore, he said as the audience broke into long applause.

Booker said he was happy to see the ideas but sorry it took so long.

'I'm happy that people like Beto O'Rourke are showing such courage now and coming forward and also now supporting licensing. But this is – what I'm sorry about, I'm sorry that it had to take issues coming to my neighborhood or personally affecting Beto to make us demand change,' the senator from New Jersey said.

'I will lead change on this issue because I have seen what the carnage creates in communities like mine, because we forget, national shootings, these mass shootings are tragedies, but the majority of the homicide victims come from neighborhoods like mine. Nobody has ascended to the White House that will bring more personal passion on this issue. I will fight this and bring a fight to the NRA and the corporate gun lobby like they have never seen before,' Booker vowed.

Warren started off her time on gun reform by clarifying the issue as an overall 'gun violence problem,' insisting that people only pay attention to mass shootings and not all of the other gun-related issues in the country.

She admitted, however, that the solution is not a 'one-and-done,' claiming it would need to be revisited several times before it would reap the intended results.

'The question we need to ask is when we've got this much support across the country… why doesn't it happen? And the answer is corruption, pure and simple,' she said.

Progressive Senators Warren and Sanders both said Congress is beholden to the gun industry and the National Rifle Association – which they claim is preventing lawmakers from moving forward on gun reform legislation.

Sanders said the NRA is determining what is happening in Washington D.C. on the issue.

'You've got an NRA, which has intimidated the President of the United States and the Republican leadership,' he said. 'I am proud that year after year, I had an 'F' rating from the NRA. And as president, I will not be intimidated by the NRA.'

Ahead of the debate Trump said he 'respects' all of the candidates, and talked up the three poll leaders: former Vice President Joe Biden , Massachusetts Sen. Elizabeth Warren, and Vermont Sen. Bernie Sanders

Ahead of the debate, President Donald Trump weighed in on the Democratic field as leading presidential candidates prepared to face off in Houston for the first time since their clash in Detroit at the end of July.

The president steered clear of his usual bag of insults, saying he 'respects' all of the candidates, and talked up the three poll leaders: Biden, Warren, and Sanders.

'If you don't make a really major mistake, he should be able to make it,' Trump said of Biden, who for the first time shares a debate stage with Warren Thursday.

'I would imagine Biden would be able to make it if he doesn't make any major mistakes, we'll see what happens.' the president said, giving the benefit of the doubt to the poll leader, who has persisted despite a series of gaffes.

Biden has been persevering despite growing attacks from rivals, focusing on his ability to beat Trump. On Thursday he rolled out a new video that fully embraced the record of former President Barack Obama.

Trump also mentioned Warren, failing to roll out his 'Pocahontas' slur, and said 'certainly Bernie [Sanders] is there,' leaving out his usual moniker of 'crazy.'

'He's number three,' Trump said, offering a casual assessment of the polls.

Asked by DailyMail.com which of the candidates he doesn't respect as he left the White House for Baltimore, a city he has characterized as rat-infested, a mellow Trump responded: 'I respect all of them. I respect every one. Let me tell you, it takes a lot of courage to run for office. I respect all of them. See that? I'm getting much better as a politician. You never thought you'd hear that answer.'

This time, the contest is in Southeast Texas – in a Republican state where Democrats continue to see growth, with gains many party insiders warn will be put at risk if Democrats veer left in the primaries.

'Texas is a liability for Republicans and the state is rapidly becoming a battleground the GOP must defend,' the Democratic National Committee said in a press release timed to the debate.

Even Democrats polling at one or two per cent don't want to let go of the opportunity to vault into position to take on Trump, who has seen his public approval rating dip since last month, after a series of angry clashes and some missteps.

A Wednesday Reuters / Ipsos poll had 57 per cent of Americans say the country is on the 'wrong track.'

Trump's approval rating is at 39 per cent in the Gallup poll, down from 42 per cent July 31st. His disapproval rating is at 57 per cent.

Andrew Yang unveils dramatic $120,000 giveaway at start of Democratic debate in bid to prove his 'universal basic income' works – to laughter from Pete Buttigieg

Democratic candidate Andrew Yang promised Thursday to give $120,000 to 10 lucky people.

During his opening statements at the third round of Democrat debates in Houston, Texas Thursday night, Yang said that 'someone watching this at home right now' would be able to win $1,000 per month for a year.

Yang is calling the initiative the Freedom Dividend Pilot Program, and will give money to 10 individuals from funds donated to his campaign.

In the days leading up to the third round of Democratic debates, Yang teased a 'surprise' that would come out on stage in Houston, Texas Thursday night.

'In America today everything revolves around the ultimately dollar,' Yang said as the first line of his opening statement. 'We have to get our country working for us again, instead of the other way around.'

'That's why I'm going to do something unprecedented tonight,' he continued. 'My campaign will now give a freedom dividend of $1,000 a month for an entire year for 10 American families, somebody watching this at home right now.'

'If you believe that you can solve your own problems better than any politician, go to Yang2020.com and tell us how $1,000 a month will help you do just that,' he promoted. 'This is how we will get our country working for us again, the American people.'

Democratic 2020 candidate Andrew Yang unveiled during the debate Thursday night that his campaign would be giving $120,000 to 10 families

Yang, promising money to supporter, was a tough act to follow – but Pete Buttigieg had to do just that.

Before beginning his opening statement, Buttigieg sighed and dropped his hand on the podium in defeat.

'It's original, I'll give you that,' he said with a smile towards Yang.

Yang, who usually falls within the second-tier of the 20 candidates running in the Democratic primary, is already personally financing this program for three families – but the ten new individuals will receive money directly from his campaign.

The three current dividend recipients are Jodie Fassi of New Hampshire, Malorie Shannon of Florida and Kyle Christensen of Iowa.

His campaign advertised that those individuals claim they are already reaping the benefits of the addition funds from being able to afford healthcare, to making home improvements and fixing cars needed for work transportation.

'The campaign is excited to work together with our supporters to help create more stories about what the Freedom Dividend means for American families. It will enable and empower citizens to pay their bills, switch jobs, take care of loved ones, and plan for the future,' Yang's campaign manager Zach Graumann said in a statement.

'It will build a trickle-up economy, from our people, families, and communities up,' he said.

The statement from his campaign also assured that the program fell within the FEC-guidelines.

'Hell yes, we ARE going to take your AR-15s!' Beto O'Rourke goes all in on gun control to applause from Democrats - but hands Republicans instant attack ad

Beto O'Rourke made a bold gun control vow Thursday night at the 22020 Democratic debate, saying: 'Hell, yes, we are going to take your AR-15s.'

The former Texas congressman was applauded by the Democratic audience but risked handing Republicans red meat for attack advertisements if he makes it to the head-to-head race with Donald Trump.

O'Rourke has made outspoken attacks on the Republicans and Donald Trump in particular over guns the centerpiece of his campaign in the wake of mass shootings in Texas, most recently at Walmart in El Paso.

But making the declaration on the debate stage reaches a wider audience - and could be used against him.

O'Rourke got heated talking about the need to eliminate assault weapons after the mass shootings in El Paso and Odessa in a passionate speech that had the audience cheering him on.

'If it's a weapon that was designed to kill people on a battlefield. If the high impact, high velocity round, when it hits your body, shreds everything inside of your body because it was designed to do that so you would bleed to death on a battlefield and not be able to get up and kill one of our soldiers.

O'Rourke got heated talking about the need to eliminate assault weapons after the mass shootings in El Paso and Odessa in a passionate speech that had the audience cheering him on

'When we see that being used against children and in Odessa, I met the mother of a 15-year-old girl who was shot by an AR-15 and that mother watched her bleed to death over the course of an hour because so many other people were shot by that AR-15 in Odessa, there weren't enough ambulances to get to them in time.

'Hell, yes, we're going to take your AR-15, your AK-47. We're not going to allow it to be used against a fellow American anymore, he said as the audience broke into long applause.'

Shortly after his intervention, his campaign tweeted a clip of it and a link to his fundraising website, suggesting he had practiced the line in advance.

There had been bickering between the candidates when they were asked about their response to the recent spat of mass shootings that have taken place in the country.

Joe Biden was asked why voters should trust him to lead on the issue when President Obama asked him to work on background checks after the 2012 Sandy Hook Elementary School shootings and a measure to expand the checks died on the Senate floor.

'Because I've got it done before,' the former vice president said. 'I'm the only one up here that's ever beat the NRA. Only one to beat the NRA nationally. I brought the Brady bill into focus and became law. And so, that's number one. Number two, after Sandy Hook, a number of things happened. It went from a cause to a movement,' he said.

The Brady Bill that Biden referred to was a 1993 law signed by President Bill Clinton was Biden was a senator from Delaware. It mandated federal background checks on firearm purchasers in the United States, and imposed a five-day waiting period on purchases, until the NCIC system was implemented in 1998.

'So, the point is, things have changed,' Biden said, 'and changed a lot.'

He then went on to praise O'Rouke for his response to the August shooting a Wal-Mart in his home town of El Paso where a mass shooter killed 22 people and injured 24 others.

'By the way, the way Beto - forgive me for saying Beto, congressman,' Biden said to O'Rourke.

Shortly after his intervention, his campaign tweeted a clip of it and a link to his fundraising website, suggesting he had practiced the line in advance.

'That's okay. Beto's good,' O'Rourke responded.

'The way he handled what happened in his hometown is meaningful. To look into the eyes of those people, to see those kids, to understand those parents, you understand the heartache,' Biden said.

But Biden was also asked why he said assault weapons cannot be outlawed for purchase by executive order.

'Some things you can. Many things you can't,' Biden said.

But Harris attacked him, using Barack Obama's 2008 campaign slogan.

'Well, I mean, I would just say, hey, Joe, instead of saying, no, we can't, let's say yes, we can,' the California senator said.

'And yes, we can,' she added. 'It is overlooking the fact that every day in America, our babies are going to school to have drills.

'Elementary, middle and high school students, where they are learning about how they have to hide in a closet or crouch in a corner if there is a mass shooter roaming the hallways of their school.

'I was talking about this at one of my town halls and this child was 8 years old, probably, came up to me. It was like it was a secret between the two of us, he tugged on my jacket and he said, I had to have one of those drills. It is traumatizing our children.'

She then praised O'Rourke for his work in El Paso and got in an attack at President Trump.

'Beto, God love you for standing to courageously in the midst of that tragedy. People asked me in El Paso, they said, you know, because I have a long-standing record on this issue.

'They said, do you think Trump is responsible for what happened? And I said, well, look, obviously he didn't pull the trigger, but he certainly been tweeting out the ammunition,' Harris said.

Booker said he was happy to see the ideas but sorry it took so long.

'I'm happy that people like Beto O'Rourke are showing such courage now and coming forward and also now supporting licensing.

'But this is - what I'm sorry about, I'm sorry that it had to take issues coming to my neighborhood or personally affecting Beto to make us demand change,' the senator from New Jersey said.

'I will lead change on this issue because I have seen what the carnage creates in communities like mine, because we forget, national shootings, these mass shootings are tragedies, but the majority of the homicide victims come from neighborhoods like mine.

'Nobody has ascended to the White House that will bring more personal passion on this issue. I will fight this and bring a fight to the NRA and the corporate gun lobby like they have never seen before,' Booker vowed.

'Have you forgotten what you said two minutes ago?' Julian Castro, 44, astonishes Democrats by hinting that Joe Biden, 76, is struggling with his memory as they clash on health care

Julian Castro, 44, unloaded on Joe Biden, 76, about his age at the Democratic debate Thursday night, implying the former vice president was having memory problems in a not so subtle shot at concerns about Biden's advancing years.

'Are you forgetting what you said two minutes ago?,' Castro snapped at him during a fierce back-and-forth on healthcare as the audience gasped at the attack line.

'Are you forgetting already what you just said two minutes ago?,' he repeated as Biden looked shocked at the punches coming his way.

Julian Castro, 44, attacked Joe Biden, 76, about his age on the Democratic debate stage Thursday night

The image of one of the youngest candidates on the stage attacking one of the oldest comes as Biden, the frontrunner for the Democratic nomination, has faced increased questions about his health.

Biden was the main target of the night from the start of the debate when he got into a three-way tiff with liberal rivals Elizabeth Warren and Bernie Sanders on healthcare.

The former vice president attacked the cost of their proposed Medicare for All, sparking a 30 minute battle between the candidates on the health care issue.

Castro, who served as Secretary of Housing and Urban Development under President Obama, joined in the bashing of Biden.

When the moderator called on him, Castro first thanked the former president for his Obamacare plan and then pivoted to attack Biden for his healthcare plan, which is extension of Obamacare.

'We owe a debt of gratitude to President Barack Obama. Of course, I also worked for President Obama, Vice President Biden, and I know that the problem with your plan is that it leaves 10 million people uncovered,' he said.

'Now, on the last debate stage in Detroit, you said that wasn't true when Senator Harris brought that up. There was a fact check of that, they said that was true,' Castro added.

Castro, who is near the bottom of Democratic polls on the race, then when on to layout his healthcare plan and get in another shot at Biden.

'I want every single American family to have a strong Medicare plan available. If they choose to hold onto strong, solid private health insurance, I believe they should be able to do. But the differences between what I support and what you support, Vice President Biden, is that you require them to opt in and I would not require them to opt in, they would automatically be enrolled. That's a big difference, because Barack Obama's vision was not to leave 10 million people uncovered. He wanted every single person in this country covered. My plan would do that. Your plan would not,' he said.

Biden defended his plan: 'They do not have to buy in. They do not have to buy in.'

And then Castro attacked him hard, implying he had forgotten what his plan involved in a not-so-subtle hint at the concerns among some Democrats about Biden's age.

'You just said that two minutes ago. You just two minutes ago they would have to buy in,' he said.

'Are you forgetting what you said two minutes ago? Are you forgetting already what you said just two minutes ago? I can't believe that you said two minutes ago that they had to buy in and now you're saying they don't have to buy in. You're forgetting that,' Castro added.

'You are automatically enrolled, ' Biden responded.

But Castro stayed on the attack.

'If you lose your job, for instance, his health care plan would not automatically enroll you. You would have to opt in. My health care plan would. That ice a big difference. I'm fulfilling the legacy of Barack Obama and you're not,' Castro said.

Joe Biden has faced questions about his health and age

Julian Castro attacked the Democratic front runner hard on his age

'That will be a surprise to him,' Biden snapped back.

Earlier in the debate, when talking about his plan in comparison to Medicare for All, Biden said: 'If you want Medicare, if you lose the job from your insurance company, from your employer, you automatically can buy into this. You don't have no pre-existing condition can stop you from buying in. You get covered. Period.'

Castro was referring to an attack line Harris threw at Biden in the second Democratic debate, which took place in Detroit in July.

She charged Biden's plan 'leaves out almost 10 million Americans.'

Fact checkers, after the debate, declared her attack line was correct.

Biden's plan - which expands the Affordable Care Act by creating a government-backed public health insurance option and increasing Obamacare's federal subsidies – would insure more than an estimated 97 per cent of Americans.

That means out of the population of 327 million in the United States, roughly 10 million would be left without any health insurance.

Castro was repeating an attack on Biden's healthcare plan that Kamala Harris originally made at the Democratic debate in Detroit in July

Biden has faced questions about his mental ability to take on President Donald Trump after a series of verbal gaffes.

But questions about his health rose after his eye was seen filling with blood during a CNN town hall debate on the climate on earlier this month.

If elected, Biden would be the oldest person ever to occupy the Oval Office.

He has said he will release his medical records and questions about his health are fair but his campaign has not said when those records will be made public.

After the fight between Castro and Biden, Pete Buttigieg stepped in to call for an end to the bickering.

'This is why presidential debates are becoming unwatchable. This reminds everybody of what they cannot stand about Washington. Scores points against each other. Poking at each other. And telling each other that - my plan, your plan,' he said.

But Castro interrupted to attack him too.

'That's called the Democratic primary election, Pete,' Castro said. 'That's called an election. That's an election. You know? This is what we're here for. It's an election.'