Democratic presidential front-runner Bernie Sanders faced off in a town hall with two Fox News hosts Monday night about who would pay for a universal healthcare system.

'Senator, this audience has a lot of Democrats in it. It has Republicans, independents, Democratic Socialists, conservatives. I want to ask the audience a question, if you could raise your hand here, a show of hands of how many people get their insurance from work, private insurance, right now?' Fox News host Bret Baier asked the audience.

More than half the audience for Fox's town hall, which was held in the center of the rust-belt in Bethlehem, Pennsylvania, raised their hand in the poll.

'OK. Of those, how many are willing to transition to what the senator says, a government-run system?' Baier asked, which was met with even more hands raising and cheers from the audience.

Sen. Bernie Sanders told an audience at a Fox News town hall the U.S. should transition to a universal healthcare system

The audience erupted in cheers when Fox News host Bret Baier, who co-hosted the town hall with Martha MacCallum, asked the audience if they would prefer a universal healthcare system

DEM HOPEFULS' CASH SO FAR IN 2019 Bernie Sanders: $18.2 million Kamala Harris: $12 million Beto O'Rourke: $9.4 million Pete Buttigieg: $7 million Elizabeth Warren: $6 million Amy Klobuchar: $5.2 million Cory Booker: $5 million Kirsten Gillibrand: $3 million Jay Inslee: $2.25 million John Hickenlooper: $2 million Tulsi Gabbard: $1.9 million Andrew Yang: $1.7 million Marianne Williamson: $1.5 million Julian Castor: $1.1 million John Delaney: $345,000 Wayne Messam $84,000 From January 1 to March 31 Advertisement

President Donald Trump insulted 'crazy Bernie' on Twitter, claiming that the audience, and Baier, were humoring him by being 'smiley and nice.'

'So weird to watch Crazy Bernie on @FoxNews. Not surprisingly, @BretBaier and the 'audience' was so smiley and nice. Very strange, and now we have @donnabrazile?' Trump tweeted Tuesday morning.

He had not tweeted about Sanders since February when he congratulated the independent senator from Vermont after he announced he was running in 2020.

Sanders, who identifies as a Democratic Socialist, says healthcare is a human right and should be free.

Baier's co-host, Martha MacCallum, asked how Sanders where the money would come from for a government-run healthcare system.

'I think everybody is in agreement that healthcare needs to be fixed in this country,' MacCallum said. 'The question is how, and my question to you was it will drive up taxes to pay for health care, and not just the wealthy will pay for that, the middle class will also pay for it. So how do you justify it?'

Sanders reasoned that this system was better because people wouldn't have to pay health insurance premiums.

President Trump said the hosts and audience were being 'smiley and nice' to 'crazy Bernie' Sanders during the town hall

Even though Sanders touts the switch as a free alternative to healthcare, he admitted that it wasn't completely 'free' and that 'somebody is going to pay'

Sanders is the 2020 front-runner among the 18 Democratic competing for the party's nomination

'You're going to pay one way or the other,' MacCallum rebutted. 'Whether it's in your income tax or your payroll tax.'

'Health care is not free,' Sanders conceded.

'Of course not, you just said it's going to be free for everyone.'

'It's going to be free of the point of when you use it, OK? Why are you so shocked by this?' Sanders asked. 'Somebody is going to pay.'

'Look, health care costs money,' Sanders continued. 'Every other country, or virtually every country, does it in the same way we do education for our kids. OK, when a kid walks into school, the kid doesn't have to take out a credit card, right? It's paid for out of public funds. That's what most countries do… Are people going to pay more in taxes? Yes. But at the end of the day, the overwhelming majority of people are going to end up paying less for health care because they're not paying premiums, copayments, and deductibles.'

Sanders is the only Democratic candidate that has had a town hall with Fox News in the 2020 cycle so far.

Democratic National Committee Chairman Tom Perez said that during the 2020 election cycle none of the Democratic debates would be hosted by Fox News.

'I believe that a key pathway to victory is to continue to expand our electorate and reach all voters,' Perez said in a statement in March. 'That is why I have made it a priority to talk to a broad array of potential media partners, including Fox News.'

Perez, however, said that recent reporting regarding President Donald Trump and his administration's relationship with Fox News, led him to reconsidering pairing with the network for the debates.

'[T]he network is not in a position to host a fair and neutral debate for our candidates,' Perez said at the time. 'Therefore, FOX News will not serve as a media partner for the 2020 Democratic primary debates.'

Sanders is leading in polling and fundraising among Democrats vying for the party's nomination.

Among Democratic primary voters, 29 per cent say they support Sanders, and his campaign raised more than $18 million in the first quarter of 2019.