HOUSTON — Two years ago, the presidential election hinged in large part on a rightward shift among working-class whites who deserted Democrats.

Tuesday’s House election may turn on an equally significant and opposite force: a generational break with the Republican Party among educated, wealthier whites — especially women — who like the party’s pro-business policies but recoil from President Trump’s divisive language on race and gender.

Rather than seeking to coax voters like these back into the Republican coalition, Mr. Trump appears to have all but written them off, spending the final days of the campaign delivering a scorching message about preoccupations like birthright citizenship and a migrant “invasion” from Mexico that these voters see through as alarmist.

In Republican-leaning districts that include diverse populations or abut cities that do — from bulwarks of Sunbelt conservatism like Houston and Orange County, Calif., to the well-manicured bedroom communities outside Philadelphia and Minneapolis — the party is in danger of losing its House majority next week because Mr. Trump’s racially-tinged nationalism has alienated these voters who once made up a dependable constituency.