A defining moment in the first set of Democratic debates came when one of the candidates barely registering in early polls, Julián Castro, launched a blistering attack on fellow Texan Beto O’Rourke for not supporting his plan to end criminal penalties for undocumented immigrants crossing the southern border.

By the next night, the question in the Democratic Party was all but settled. Of the 10 candidates onstage Thursday, nine raised their hands to say they backed Castro’s plan. All 10 said they would back federal health subsidies for undocumented immigrants, an idea President Barack Obama rejected a decade earlier.

“We are moving toward a more inclusive Democratic Party, which is great for Americans of all different backgrounds,” Castro, who was secretary of Housing and Urban Development during the Obama administration, boasted afterward.

He was not the only one cheering.

“How about taking care of American Citizens first!?” President Trump tweeted triumphantly after the candidates embraced health coverage for the undocumented. “That’s the end of that race!”

With a full embrace of liberal positions on hot-button issues such as immigration, health care, taxes and abortion, the Democratic presidential field has effectively abandoned the strategy that propelled the party to a landslide victory in the 2018 midterms, when Democrats flipped 43 GOP House seats and won 31 districts that Trump carried in 2016. The sharp shift to the left, laid bare over the course of two nights last week on the Miami debate stage, has scrambled the country’s political dynamics headed into a 2020 campaign in which Democrats hope the 2018 results, combined with Trump’s relatively low approval ratings, will put them in a strong position to retake the White House.

Last year’s midterm strategy focused on what party leaders viewed as a sensibly moderate message designed to attract centrist voters. In that campaign, Democratic congressional candidates denounced GOP tax increases for the middle class in Trump’s 2017 tax cut and blasted Republican plans to take away federal protections for preexisting conditions in private insurance.

But many of the leading Democratic presidential candidates are running on a Medicare-for-all plan that would replace private insurance entirely for most Americans and raise middle-class taxes to pay for it. Several of the candidates support plans to not just increase background checks for guns but buy back guns already in circulation. They are also highlighting social issues that Trump has taken a political stand on in the past, including police misconduct, transgender rights and immigration.

“These are not mainstream proposals. Think about it. They are way to the left of Barack Obama,” said Jim McLaughlin, a pollster working on Trump’s reelection campaign. “They are talking about middle class and small business tax increases, no restrictions on abortion. How do you think these things are going over in places like Pennsylvania and Ohio?”

Democratic strategists from the 2018 campaign agree there is a danger.


Candidates wave to the audience Thursday during the second night of the first Democratic presidential debate. (Jayme Gershen/Bloomberg News)

“We should not be deploying strategies right now that make the national battlefield smaller,” said Dan Sena, the former executive director of the Democratic Congressional Campaign Committee. His research on the electorate after Trump’s 2016 win concluded it was a mistake to get into a simple base turnout fight against Trump, who has proved remarkably successful at motivating non-college-educated white voters to go to the polls.

“The Democrats run a real danger of letting the small details define them,” he said. “Some of those smaller details may not be in lockstep with where the rest of the country is.”

The molting of party identity during presidential elections is a perennial feature of American politics. But the historically large Democratic field, the continued economic frustrations of many Americans and the passions stirred by President Trump appear to have set up the Democratic Party for a particularly transformative year.

Even former vice president Joe Biden, whose campaign is anchored around the promise of a return to the pre-Trump political era, has shifted his positions in recent months, embracing federal health coverage for undocumented migrants and federal funding for abortion.

In the short term, the new Democratic messaging is aimed less at suburban swing voters in key states like Wisconsin and Michigan than at liberal donors clustered in coastal cities and nonwhite voters in the party’s base, who tend to be more liberal and hold significant sway over the nominating fight.

But it is not clear how dramatically the candidates plan to pivot if they do win the nomination, and whether they will be successful. Many reject the argument that more liberal policies will alienate needed voters. They point to Trump’s inability to use immigration fears of migrant caravans to stop a Democratic wave in 2018.

“Those are all right-wing talking points that get thrown out,” said Castro, who has been pushing his party to the left by arguing that Democrats can win states like Arizona, Texas and Georgia if they energize young and minority voters. “It’s the same old lie.”

His online fundraising in the 24 hours after the debate exceeded the money he brought in for his campaign launch, he said.

Candidates such as Sen. Elizabeth Warren (Mass.), Sen. Kamala D. Harris (Calif.) and Sen. Bernie Sanders (I-Vt.), who all support replacing most private insurance with an expanded Medicare program, argue the best way to beat Trump is to transform political dynamics by arguing a larger role for government would improve the lives of the middle class.

Warren and Sanders, in particular, have cast Trump as a symptom of broader rot in the American political system, not the root cause. The larger problem can only be fixed, they argue, with dramatic policy changes that shift resources from the wealthy, including new taxes on Wall Street, corporate profits or the richest Americans. They contend that message will ultimately resonate with many of the same working-class white voters who supported Trump in 2016.

“When you’ve got a government, when you’ve got an economy that does great for those with money and isn’t doing great for everyone else, that is corruption, pure and simple,” Warren said in her first debate answer on Wednesday. “We need to call it out. We need to attack it head on. And we need to make structural change in our government.”

Jim Margolis, a senior adviser to Harris who worked on both of Obama’s presidential campaigns, emphasized the importance of framing for voters the coming policy debates around issues like Medicare-for-all. “They care about whether they can keep their doctor,” he said. So it’s important for candidates to highlight that “91 percent of doctors are in the Medicare program,” he said.

As for health benefits for undocumented immigrants, Harris viewed it as a question of values, Margolis said.

“She will also say, ‘I am not going to deny anyone ever health care or education or public safety. I’m not doing it. Period,’ ” he said. “And so there are implications to that.”

Recent police shootings of black men were also a theme on both nights, raising a “law and order” issue Trump has historically employed to motivate his voters.

“Please don’t be too nice,” Trump told a conference of police officers in 2017, before joking that it would be okay if police officers stopped trying to protect handcuffed suspects’ heads when they place them in cars.

At Thursday’s debate, Rep. Eric Swalwell (Calif.) told South Bend, Ind., Mayor Pete Buttigieg that he should fire the chief of police after a police shooting of a black man in that city, even before the completion of an investigation into the event.

Sen. Michael F. Bennet (Colo.), former chairman of the Democratic Senatorial Campaign Committee, was the only candidate not to raise his hand Thursday when asked if he supported decriminalizing border crossing. He has also been a fierce critic of Medicare-for-all, arguing instead for creating a public insurance option that Americans can choose to join.

“What I think is impossible is the idea that we are going to take insurance away from 180 million people,” Bennet said in a Friday appearance on MSNBC. “Here we are saying, if you like your insurance, we are going to take it away from you, and you can’t win a Senate race in Colorado being for Medicare-for-all, and I would be surprised if you could win one in Arizona or North Carolina.”

Other veterans of Obama’s 2012 reelection also chimed in with concern, not just for the coming election but for the prospect of governing, even if Democrats recapture the Senate and hold the House.

“I wonder if we’re solving a problem that is not there and spending the vast majority of our political capital on it,” said Obama’s former campaign press secretary Ben LaBolt, who is unaffiliated in the 2020 race. “Expanding upon and improving Obamacare accomplishes the vast majority of goals that Democrats are looking for.”

Polling shows that single-payer health care remains a confounding idea for many Americans. Recent Kaiser Family Foundation polls have found that 56 percent of the nation favors Medicare-for-all, compared with 74 percent of Americans who support expanded Medicare as an option for younger Americans in addition to private insurance.

When the same people were told that a Medicare-for-all plan would raise taxes and eliminate private health insurance, support fell to 37 percent. Most people surveyed under the age of 65 with private health insurance falsely believed they would keep their coverage under the proposal.

Rick Tyler, a conservative Republican strategist who has become a vocal critic of Trump, said he believes Democrats are playing right into Trump’s hands.

“They are not talking to the blue-collar workers that I understand that vote in Pennsylvania and Michigan,” Tyler said. “Are they seriously capable of choosing a nominee who is going to beat Donald Trump? Right now, I have my doubts.”