Read: President Trump still wants to repeal Obamacare

But the Republican pollster Gene Ulm says that if Democrats veer left, they are taking a risk, particularly with well-educated suburban voters. Those voters are already cross-pressured between their personal “reticence” about Trump (Ulm’s phrase) and their satisfaction with the economy. Adding a historically ambitious liberal agenda to the scales, he argues, could tip those conflicted voters toward choosing Trump for a second term, especially if they conclude that the Democratic proposals will threaten the strong economy. “These types of issues definitely will decide where the suburbs will go, where white college-educated people will go,” he says.

Trump and other Republicans, Ulm adds, face a mirror-image threat. While many voters may feel that some of the solutions emerging from the revivified Democratic left go too far, he says, they do see the policies responding to legitimate problems that Republicans sometimes appear to discount. “Voters oppose the Green New Deal because of this crazy price tag and wacky stuff that it’s going to do, but it doesn’t mean they are against the environment,” Ulm says. “They oppose Medicare for all, but that doesn’t mean they are against people being able to have access to health care. They are against free college for everybody, but that doesn’t mean college ought not to cost less.” Voters, he adds, give Democrats “some credit for good intentions here.”

And indeed, other ideas emerging from the Democrats’ 2020 field have drawn consistent support across racial lines in recent polls. A majority of college-educated and non-college-educated whites, as well as preponderant majorities of blacks and Latinos, backed extensive student-loan forgiveness in the Quinnipiac poll. Lopsided majorities of all four groups in the Kaiser survey supported allowing more adults to buy into Medicare, as Biden, former Representative Beto O’Rourke, and other 2020 candidates have proposed.

Democrats are also on relatively more solid ground in proposing to rescind or restructure Trump’s tax cut: In a March Pew Research Center poll, about three-fourths of African Americans, nearly two-thirds of Latinos, and a slight majority of college-educated whites said they oppose it (although only about one-third of blue-collar whites said the same). And in contrast to the mostly negative response to the 70 percent top income-tax rate, Warren’s proposed wealth tax on the largest fortunes drew support from three-fifths of all adults in the Quinnipiac survey, including significant majorities of college-educated whites, Latinos, and African Americans, and a narrower majority of non-college-educated whites.

Voters have repeatedly demonstrated that if they believe presidential candidates care about their lives, they are willing to overlook disagreements over important components of their agenda—or even, as in Trump’s case in 2016, serious doubts about their character and temperament. But in choosing between candidates offering incremental change (such as allowing more Americans to buy into Medicare and reducing student debt) or revolutionary transformation (such as a government takeover of the health-care system and free four-year public college), Democrats will still be placing an implicit bet about the coalition they hope to assemble against Trump.

White voters in these new polls—including the well-educated ones moving away from Trump’s insular definition of the GOP—are flashing an unambiguous yellow warning light about Democrats’ most ambitious and expensive ideas to expand government’s reach. If Democrats barrel through that signal in 2020, they will be wagering that they can beat Trump with a very different coalition—that relies more on enhanced minority and youth turnout—than the one they marshaled to recapture the House in November.