South Carolina hasn’t sent a newly elected Democrat to Congress for 25 years. But on Tuesday, voters in the Charleston area broke form and chose a Democrat over a Republican endorsed by President Trump.

That result might seem like an outlier, given South Carolina’s strong Republican tradition. But it is more evidence of a powerful new factor in politics: the nation’s growing educational divide.

Democratic pickups in House races in Oklahoma and Georgia might also have seemed unexpected, given that Republicans hold the major, statewide offices in both states. But as in South Carolina, the outcomes fit a pattern of voters with bachelor’s and advanced degrees swinging away from the GOP. White voters with lower educational attainment, meanwhile, have shifted toward the GOP.

Of the 34 House districts that Democrats picked up from Republicans as of Friday’s tallies, 29 are in the top half among all House districts for educational attainment, meaning more than 30% of adults there have bachelor’s or more advanced degrees.

Democrats now represent 27 of the 30 House districts with the largest concentration of college-educated Americans. Before Tuesday, they held 20 of those districts.