Kenneth C. Frazier, chief executive of Merck, the pharmaceuticals company, on Monday resigned from President Trump’s American Manufacturing Council after the president failed to directly condemn the white nationalist protesters at the center of violent protests in Charlottesville, Va., over the weekend.

“America’s leaders must honor our fundamental values by clearly rejecting expressions of hatred, bigotry and group supremacy, which run counter to the American ideal that all people are created equal,” Mr. Frazier said in a statement. “As C.E.O. of Merck and as a matter of personal conscience, I feel a responsibility to take a stand against extremism.”