A new HuffPost/YouGov poll finds a sharp rise in the percentage of Trump voters who do not think the U.S. bears responsibility to do anything about the fighting in Syria. Apparently, President Trump’s pullout -- which has created an unfolding disaster there, including the threat of a reconstituted Islamic State -- may be driving Trump voters away from any sense of responsibility for that region. Which raises a question: What will happen to the GOP in the After Trump era? Will it become a more nationalist party, along the lines of the “America first” vision that Trump has been articulating...