WASHINGTON — In her first national forum as a presidential candidate, Sen. Kamala Harris (D., Calif.) casually embraced the idea of eliminating private health insurance in favor of a Medicare for all Americans.

Sen. Cory Booker (D., N.J.) has pushed for a pilot program that would guarantee a federal job paying $15 an hour to anyone who seeks one, with an eye toward expanding it nationwide. Sens. Bernie Sanders (I., Vt.) and Elizabeth Warren (D., Mass.) have plans to sharply raise taxes on some of the very richest Americans. And on Thursday, when liberal Democrats rolled out the Green New Deal plan for eliminating U.S. net carbon emissions in a decade, numerous candidates embraced it, including Booker, Sanders, Warren and Harris.

For many Democrats running for president or likely to, incrementalism is out. Bold is in.

It’s a dramatic shift from three years ago, when Sanders was derided by some as a fringe candidate and his Medicare-for-all plan attacked as fantasy. Hillary Clinton, a seemingly safe choice known for small-bore pragmatism, was swamped as then-candidate Donald Trump stirred passions with attack lines and a vow to help working people with huge, if unrealistic, promises.

Now, the early crop of Democratic contenders is arguing for their own set of big, aggressive actions to take on inequality, health-care gaps, and climate change.

“When I ran for president in 2016, we had the opportunity to raise issues before the American people which had not been raised for a number of years, and I think we were able to break through,” Sanders said in an interview. “The American people have moved toward a much more progressive economic agenda, in terms of health care, in terms of wages.”

Several Democrats said Trump has emboldened their candidates by pushing past old boundaries and by posing such a threat that he has inspired a robust response.

“The Trump presidency has widened the aperture of what’s acceptable debate in the country, and I think there’s a hunger for boldness to meet this political moment,” said Neera Tanden, president of the liberal Center for American Progress. “People recognize that Trump offers kind of radical ideas and that our ideas are better.”

Even Pennsylvania Sen. Bob Casey, a relatively moderate Democrat with an even temperament, was on board. “With the challenges we have,” he said, “we have to think big.”

Primary motivation

With such a crowded and growing field of presidential hopefuls, candidates are also jockeying to make an impression, said Mark Mellman, a Democratic pollster.

“People really need to distinguish themselves, and they can’t let someone else get their big idea first,” Mellman said.

Some liberals argue that just by raising these ideas, they are widening the sense of what is possible and moving even compromise positions further left.

But the move for sweeping reforms hasn’t been embraced by every contender, or every Democrat.

“We’ve got to tread carefully ... and not say things that are going to come back to haunt us in the general election, when somebody takes out a calculator and starts adding these things up,” said former Gov. Ed Rendell, the onetime chairman of the Democratic National Committee.

In an interview, he predicted that Trump would seize on the new ideas to label Democrats as socialists.

Sure enough, in his State of the Union speech a few days later, Trump intoned: “Here in the United States, we are alarmed by new calls to adopt socialism in our country.”

Rendell, arguing that Democratic voters will show up to vote against Trump “whether you’re running for president, whether I’m running for president, or whether Joe Biden is running for president,” pointed to the party’s results in 2018, when liberal stars such as Georgia’s Stacey Abrams and Florida’s Andrew Gillum lost, while largely moderate candidates won 43 Republican-held House seats and several governor’s offices in Midwestern swing states.

“We’re not running to carry California and New York; we’re going to carry California and New York," Rendell said. “We’re running to carry Pennsylvania, Wisconsin, Michigan, Florida, and Ohio.”

A CNN poll released Wednesday suggested that a majority of Democratic voters might agree: 49 percent of Democrats or Democratic-leaning voters surveyed said having a good chance to defeat Trump is an “extremely important” factor in whom they support in the primary. Just 25 percent rated a candidate’s holding progressive positions as equally important.

Tanden said Democrats agree on general principles, such as expanding health care, but are likely to have a substantial debate about how to get there.

“Being able to assemble an electoral coalition is as important to Democratic voters as any particular issue,” she said.

Competing perspectives

So far, the argument has been steered by Democrats who come from deep-blue states like New Jersey, California, and Massachusetts. Other candidates likely to join, however, may strike different notes, even if they also push liberal ideas.

Sen. Sherrod Brown (D., Ohio) told Yahoo! News that he backs the goal of Medicare for all but that expanding the program to people aged 55 and older is more attainable right now. A progressive who has consistently won in a right-leaning swing state, he has touted his success in expanding the Earned Income Tax Credit, and his proposal to do it again under a plan that could help 50 million Americans take home more money, according to aides.

“It’s not fighting for our progressive values or getting things done — it’s both," Brown said in a statement.

Another likely entrant, Sen. Amy Klobuchar, is mostly known for a businesslike, nonconfrontational approach that has made her popular across party lines in Minnesota. Biden, the former vice president, has often had a more pragmatic outlook. And in late January former New York Mayor Michael Bloomberg blasted “pie in the sky" ideas "that we never are going to pass, are never going to afford.”

Even among the more liberal voices, Booker has rejected the idea of eliminating private insurance and Harris’ campaign said she, too, would be willing to accept more incremental steps on expanding Medicare. Each has supported Medicare-for-all bills but also measures that would take more modest steps.

The debate is unfolding as Trump struggles to deliver his signature proposal — a wall on the Southwestern border funded by Mexico, illustrating that big promises can be hard to deliver.

Liberal advocates counter that they are proposing ideas that are both popular and already tried in Western democracies such as Canada (nationalized health care) and Germany (free college tuition).

Warren’s tax plan, a 2 percent tax on a person’s net worth above $50 million, and 3 percent over $1 billion, won 61 percent support in a recent Politico/Morning Consult poll.

Expanding Medicare to all Americans, and replacing private insurance, garnered 56 percent support in a January poll by the nonpartisan Kaiser Family Foundation, which focuses on health-care policy. But less drastic options, including allowing people to voluntarily buy into Medicare or expanding it to people aged 50 and up, won substantially more backing.

About 60 percent of people opposed Medicare for all, meanwhile, after being told it might cause tax increases or eliminate private insurance.

“Once you get just the least bit below the surface and you start to look at the downsides of these far-left policies, they start to lose their appeal,” said Sen. Pat Toomey (R., Pa.). “It’s not going to be hard to convince Americans that Venezuela is not that successful.”

The early 2020 contenders seem undeterred.

“We’re the party of Social Security. We’re the party of Medicaid and Medicare,” Booker said in an interview Wednesday, before his first official campaign swing, to Iowa and South Carolina. “We’ve been a [party] that’s moving this country forward toward greater justice for all, greater fairness for all, for a long time, and I’m not sure that this is anything new.”