In interviews, some white Americans said that Trump’s rise and the overt racism and xenophobia voiced by some of his supporters have heightened their awareness of racial fissures.

But news reports about African Americans dying during encounters with officers have been especially jolting, providing whites a glimpse of what blacks long have insisted was commonplace.

Patricia Wudel, 63, the white executive director of a hospice center for the homeless in the Adams Morgan neighborhood, said she realized that her sense of the African American experience was far too limited several years ago as she ate breakfast with colleagues after a Florida jury exonerated George Zimmerman in the shooting death of Trayvon Martin.

“I said, ‘I can’t believe they let that guy off,’ ” Wudel recalled. A black woman seated next to her, she said, “so close, our arms were touching — had tears coming down her face and she whispered, ‘I always knew he would.’ ”