MIAMI (Reuters) - Democratic presidential contenders battled over healthcare coverage and border policy on Wednesday during a surprisingly heated first debate that laid bare the party’s divisions on whether to abolish private insurance and shift to a Medicare-for-All system.

In the first round of back-to-back debates, several of the lesser-known candidates vied for attention in the crowded race to take on President Donald Trump, shouting over one another to grab the spotlight and prove they are capable of standing up to the Republican in the November 2020 election.

The Democratic contenders repeatedly attacked Trump, saying his economic policies benefited the wealthy at the expense of working Americans, and calling his border policies heartless.

“On January 20, 2021, we’ll say ‘Adios’ to Donald Trump,” said former Housing Secretary Julian Castro.

But they also turned their fire on each other, most often targeting Beto O’Rourke. The former congressman tangled with Castro, a fellow Texan, on border policy, and New York Mayor Bill de Blasio on healthcare.

The intensity of the exchanges after six months of a relatively mild campaign reflected the high stakes in what could be a make-or-break moment for some of the contenders struggling to be noticed in the Democratic field of more than 20 candidates.

No one mentioned front-runner Joe Biden, who will take the stage with top rival Bernie Sanders and eight other candidates in the second debate on Thursday night.

The battle over healthcare began when the candidates were asked to raise their hands if they support eliminating private health insurance. Only U.S. Senator Elizabeth Warren and de Blasio did so, but they quickly challenged the other eight candidates on stage.

Warren, a leader of the party’s progressive wing who has been surging in opinion polls, said private insurance was taking advantage of Americans. She backs a government-sponsored Medicare-for-All approach and criticized those who say it is not politically feasible.

“What they are really telling you is they just won’t fight for it. Healthcare is a basic right, and I will fight for it,” she said.

But former U.S. Representative John Delaney, an outspoken critic of Medicare for All who supports a universal healthcare approach that includes private insurance, said Democrats should not throw away a system that some Americans are happy with.

“I think we should be the party that keeps what’s working and fixes what’s broken,” Delaney said.

After years of defending former Democratic President Barack Obama’s landmark healthcare law known as Obamacare from Republican attempts to repeal it, Democrats have struggled during the campaign to agree on the best approach to fixing it.

The Medicare for All approach pushed by Warren and Sanders, which has gained support in Congress, would create a government-operated plan that eliminates private insurance. It is modeled on the Medicare government healthcare program for seniors.

O’Rourke said private insurance was “fundamental to our ability to get everybody cared for,” but de Blasio cut him off.

“Congressman O’Rourke, private insurance is not working for tens of millions of Americans when you talk about the copays, the deductibles the premiums - it’s not working. How can you defend a system that’s not working?”

‘BORING!’

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O’Rourke also came under attack from Castro over the separation of families and detention of migrants at the southern border. Castro said he would decriminalize border crossings by migrants, which he said had led to the separation of families. He challenged O’Rourke and others to support him.

O’Rourke said that as a congressman he helped introduce a bill that would ensure that those who are seeking asylum and refuge in the United States are not criminalized.

Castro responded: “I’m not talking about the ones that are seeking asylum, I’m talking about everybody else.” He accused O’Rourke of not doing his homework.

Trump hinted he would not tweet his reactions to the debate live. It was taking place as he flies aboard Air Force One to Osaka, Japan, for a G20 summit.

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But shortly after it began, he could not help himself. “BORING!” he tweeted.

“This debate was the best argument for President Trump’s re-election and should really be counted as an in-kind contribution to the President’s campaign,” Kayleigh McEnany, the Trump campaign’s spokeswoman, said in a statement.

“The far-left, socialist policies Democrats embraced tonight were akin to a mutual political suicide pact,” she said.

The debate was an opportunity for some of the less-noticed candidates to step out of the shadow cast by Biden, a former vice president, and Sanders, a senator from Vermont.

U.S. Senator Cory Booker had the most speaking time in the debate at about 11 minutes, according to the New York Times and other media trackers. He was followed by O’Rourke, Warren and Castro. Washington Governor Jay Inslee had the least.

Several of the contenders took aim at corporate America, saying it did not pay enough in taxes, repaid government bailouts by shifting jobs overseas and charged too much for its products.

“Who is this economy really working for? It’s doing great for a thinner and thinner slice at the top. It’s doing great for giant drug companies. It’s just not doing great for people who are trying to get a prescription filled,” Warren said.

Inslee said he was the only candidate on the stage who had passed a public healthcare option and a law protecting a woman’s right to reproductive health and health insurance.

That drew a sharp response from Senator Amy Klobuchar.

“There are three women up here who have fought pretty hard for a woman’s right to choose,” she said, looking at Warren and congresswoman Tulsi Gabbard.