The latest such evidence comes in a new study released today by Navigator Research, a consortium of Democratic research and advocacy groups. The report, provided exclusively to The Atlantic, examines a group that many analysts in both parties believe could prove to be the key bloc of 2020 swing voters: Americans who say they approve of Trump’s management of the economy but still disapprove of his overall performance as president. And it shows Trump facing significant headwinds among that potentially critical group, partly because of the divisive language and behavior he’s taken to new heights, or lows, since last weekend—tweeting about the congresswomen and encouraging his supporters to attack them as well.

Read: ‘Send her back’: The bigoted rallying cry of Trump 2020

“The main takeaway from this analysis is that while some Americans might be giving Trump positive marks for his economic performance, they are strongly held back by three things: the values that they have, the views they have on other noneconomic issues, and some very real concerns about Trump’s character and temperament,” says Bryan Bennett, an adviser to Navigator Research.

This conflicted group looms so large over 2020 because about half (or even slightly more) of voters express support for Trump’s management of the economy, but only 40 to 45 percent of them give him positive marks on his overall performance. That difference could be the tipping point between a coalition that places Trump close to the comfort zone for presidents seeking reelection—support from about half of Americans—and one that leaves him trying to secure a second term with positive marks from a much smaller circle. The only presidents since 1952 who sought reelection with approval ratings below 50 percent—Gerald Ford, Jimmy Carter, and George H. W. Bush—all lost.

The conflicted voters, if they break for Trump, bring him “in range” to win, says the GOP pollster Gene Ulm: “He’s incredibly close. Can I predict that he’s going to win Michigan, Wisconsin, Pennsylvania? No, I can’t do that. But he is within spitting distance of that 47 [or so] mark he needs to win when you look at these chunks of people.”

These voters consistently register as a substantial group. Since April, polls from CNN, Quinnipiac University, and ABC/The Washington Post have found that between 16 percent and 19 percent of Americans who approve of Trump’s handling of the economy still disapprove of his overall job performance. That’s a very high disparity by historical standards: The NBC/Wall Street Journal poll has found that Trump’s approval rating among Americans who say they are satisfied with the economy is running 16 to 20 percentage points lower relative to the approval ratings of George W. Bush and Barack Obama.

The Navigator research, based on the cumulative results of all six national surveys the group has conducted since the 2018 election, defines this group slightly more narrowly: Its results put about 10 percent of Trump’s voters, or 6 percent of all voters, in this camp. (The reason: Navigator, compared with most public polls, records a slightly lower approval rating for Trump, both overall and on the economy.)