One group has emerged as especially alienated from the president: college-educated white women. The group ordinarily leans Democrat, but only slightly: Since 1992, Democrats have never carried more than 52 percent of their votes in House elections, and Hillary Clinton won 51 percent of them in 2016. However, this week’s NBC/WSJ poll found that 63 percent of them now disapprove of Trump and 62 percent intend to vote Democratic in November.

By itself, such a sharp move among college-educated white women could doom many Republicans clinging to their seats in white-collar districts in major metro areas. Reinforcing the danger is the president’s decline since 2016 among blue-collar white women and college-educated white men. House Democrats only won about 35 percent of each group in both the 2010 and 2014 midterms. This week, both groups split about evenly in their congressional preferences in the NBC/WSJ survey.

Even if Republicans energize their base enough to avoid the worst in November, polls are clarifying the long-term risks of welding themselves to Trump. With Millennials poised to pass the baby boom in 2018 as the largest generation of eligible voters, the NBC/WSJ survey found that two-thirds of Millennial women disapprove of Trump and nearly three-fourths intend to vote Democratic for Congress. (Democrats had a much narrower six-point lead among Millennial men.)