Tim Scott, the lone black Republican in the Senate, delivered a pointed lecture on America’s 300-year legacy of racism to President Trump on Wednesday in response to what he called Mr. Trump’s “sterile” response to the riots in Charlottesville, Va., last month.

The president invited Mr. Scott, a conservative from South Carolina who had expressed disgust with Mr. Trump’s equivocal reaction to the white supremacist protests that left one woman dead, to the Oval Office for what Mr. Trump’s staff described as a demonstration of the president’s commitment to “positive race relations.”