Well, this year they're certainly going to help. Ron Brownstein has some recent polling date (note: all data collected before the confirmation of Brett Kavanaugh as Supreme Court justice).
"Over the past several months, polls consistently have shown Democrats on track to amass much wider -- and even unprecedented -- margins with those women in 2018. The latest CNN and USC Dornsife/Los Angeles Times polls each showed Democrats capturing an astounding 67% of college-educated white women, while the Pew Research Center's most recent survey put their support at 63%. The latest Fox News and NBC/Wall Street Journal polls showed Democrats drawing just below three-fifths of these women....
Just as important, a procession of recent state polls have found the Democrats' advantage among college-educated white women persisting in every region of the country, not just in liberal states along the coasts. The most recent CNN surveys showed Democrats Kyrsten Sinema in Arizona and Phil Bredesen in Tennessee each carrying almost three-fifths of them.
Recent NBC/Marist surveys have found Democrats Sherrod Brown winning about two-thirds of these women in the Ohio Senate race and Andrew Gillum capturing nearly three-fifths of them in the Florida governor's race. The most recent Marquette University Law School survey in Wisconsin found Democratic Sen. Tammy Baldwin winning about two-thirds of them in the Senate race and over three-fifths backing Democrat Tony Evers in the governor's contest. Even in heartland states steadily shifting toward the GOP, NBC/Marist polls found Democratic Sens. Claire McCaskill in Missouri and Joe Donnelly in Indiana attracting support from a majority of these women."
Impressive! But it's important to stress that Democratic gains are not confined to white college educated women, particularly in the Midwest. As Brownstein notes in another article:
"[F]or Democrats [there] are...sprouts of recovery among working-class white voters—or at least working-class white women. In general, midwestern blue-collar white men still overwhelmingly favor Republicans in this fall’s contests. But in Ohio, the NBC/Marist poll showed Brown leading among non-college-educated white women by double digits, and Cordray trailing only slightly. In Wisconsin, those women prefer Evers narrowly and Baldwin by a 17-point margin."
To the extent Democrats do well this fall, it will also have a lot to do with movement of these voters to the Democrats, particularly in certain areas of the country. It is important to remember that nationally white college women are perhaps 1 in 6 voters, while white noncollege women are close to 1 in 4. That disproportion is even greater in critical Rustbelt states. Looking past 2018 to 2020, Democrats would do well to remember that whatever moves white noncollege women toward the Democrats is not likely to be the same as the cluster of social issues that loom so large for white college women. Building the next successful Democratic coalition depends a lot on understanding these differences.
Or, to put it more bluntly, white college educated women will not save the Democratic party, at least by themselves. There is no one demographic savior for the Democratic party. Only a big tent, in the medium to long run, is likely to be successful.