We now have something like consensus: The rise of Donald Trump portends the end of the Republican Party as we know it. As longtime GOP operative and commentator Steve Schmidt said last week, “The Republican Party has an outstanding chance of fracturing.” Trump’s opponents, inside and outside the party, are united in the belief that he has almost single-handedly undone an institution founded on the eve of the Civil War that has lasted for more than 150 years and has immeasurably shaped the United States.