“This is exactly the process of how social change happens,” Ms. Fetner said. “It’s not because all of a sudden there is more racism now than there was a few weeks ago. It’s that the absolute condemnation of those most abhorrent views is crumbling away because the president isn’t fulfilling that role.”

Ms. Fetner has studied the transformation in views on gay rights and same-sex marriage. The shifts around race and gender similarly reflect not just widening acceptance of equality, but also the rising condemnation of anyone who vocally opposes it.