“This is exactly what we wanted him to do,” Rep. Trey Gowdy of South Carolina said Sunday, asserting that “for those of us who’ve supported Bob Mueller from day one, and said give him the time and resources and the independence to do his job — this is his job.”

“What this indictment tells us,” Mr. Gowdy added, “is that Russia is not our friend. Russia has tried to subvert the fundamentals of our democracy.”